I've been known to offer up a post that strikes out at product weaknesses, or is aimed at correcting some errant posts I read of others. Usually, it is clear what their post intended to convey, or it was clear that there is a product weakness.
As I usually try to do, I base my comments on knowledge as well as 'hands-on' experience in the field for over four decades. I consider myself to be at least in the upper-half of knowledgeable and experienced detectorists around, and so I will reply as follows:
"Rock bottom on my list."... I have honestly stated that I felt Minelab erred in the presetting of the GB for the X-Terra 30 because it is too low (too negative) for many of the ground environments I hunt that are rather mineralized.
The other two X-Terra's, the '50' and the '70', are certainly competitive in the way of features and potential in their price range.
What I do not see mentioned is your "list" in order to be able to ascertain just what it is you're looking for or referring to.
"Looks like the M6 is a better machine for fast response and coil selection."... I will have to admit that I feel the White's M6 is a better pick over any X-Terra ... IF the user is planning to hunt in trashy sites or those with dense brush or building rubble. The reason is because the M6 has two smaller factory coils available, as well as some from two after-market coil makers.
As for "fast response," all I can say is I do like the M6, but I also like the X-Terra's quick response. The White's and Minelab models do have some subtle differences it response and recovery characteristics, but neither are slow responders.
However, you didn't specify which X-Terra you wanted to compare the Matrix M6 with and that's too open.
"How about a shoot-out between the M6 and Xterra?"... Again, there are three X-Terra models and two 'class' models from White's. The MXT and M6. You would have to specify which model(s) you would want to compare, and then make those comparisons based upon models in a similar price range.
"Can't wait for promised coils to exploit the features of this machine."... I am going to have to agree here. Over 90% of all my detecting, regardless of brand or model, is accomplished with a smaller-than-stock search coil. Therefore, I am eager to see what the smaller coil for the X-Terra will,be and how well it will work.
But you sort of tripped yourself up here because instead of being negative about the X-Terra series, you acknowledge that they have some potential because YOU stated "to exploit the features of this machine", and to me, that gives them credit for having some unrealized potential that we just can't appreciate until we get a smaller coil for them.
"Rumors and not official company releases of promised coils to explore the features of the '70 can only lead me to the conclusion that the owners are to be 'in' for the pound as well as the penny."... It would be nice if a manufacturer would initiate forum posts to clarify some things like this.
"Six months is too long to wait for for a coil that should have been released as part of the full line."... I will not argue this point with you because I feel it is quite valid. Consumers should not have to wait for some of the more desired and anticipated search coil sizes, especially when a new model is introduced.
R&D should address these concerns and it should be a vital part of product development to coincide with a detector model's release. And it has been, and will be, much longer than a 6-month wait!!!
"The "flagship" needs a few more sails, or Sales to get the serious detectorist to come on board."... If by "flagship" you mean the top X-Terra model, I am of the opinion that the main issue that has hampered it's sales has been the lack of a smaller coil.
"You guys must be gluttons for punishment, like bulldogs that won't let go. The resale is poor and a consumer is to wait for support."... I'd like to argue this point, too, but a glance at some of the "classifieds' forums does reflect a poor resale for the X-Terra models, especially the X-T 50 and X-T 30. Again, I wonder if some of this is maybe attributable to the lack of versatility due to not having a smaller search coil?
On the other hand, a savvy detectorist, especially one who has enough experience with a good X-Terra 70, might just want to take advantage of some of the 'good buys' out there in order to be ready for the release of a smaller coil.
"I cannot buy a product that 'automatically' decides to turn itself off and, as a line, has to be returned for service. No recalls, no consumer info."... A handful of incidents do not n epic proportion make. A new product is always going to have a few little things surface, but these issues were taken care of, and the detectors continued to work well.
"There is no reported benefit to using the other frequency/coils except for the feature itself. I would rather buy a machine that is well designed around one frequency than a does-it-all machine that is mostly used at one frequency."... ready for an argument? Well, keep waiting. While I do see some benefit in using the 18.75 kHz coils, I do NOT see anything earth-shattering. matter of fact, against my Shadow X5 and another I tried at a similar frequency, the X-Terra's w/high-frequency coil didn't fair all that well.
I was hoping the lower-frequency 3 kHz coil would help with depth on the higher-conductive silver coins, but I haven't been impressed when comparing the performance afield against a number of models in the 5 kHz range and lower.
In my opinion, the X-Terra series is "at it's best" when operated at 7.5 kHz. What I want to see, however, is a better smaller coil selection .. in that frequency.
"You would have done well to buy the '30 for coin searches. You have chosen poorly but based on the marketing, you are marked."... Is it me, or are you directing your comments toward an un-named individual? If you're simply suggesting that the X-Terra 30 would be a better buy for anyone who just wants to coin hunt, you are drastically WRING!
The X-Terra 30 doesn't have a good preset GB for most locations, and it lacks any internal or external GB adjustment to correct that. In addition, the X-Terra 30 doesn't offer nearly as many function features as do the X-Terra 50 or X-Terra 70, both of which are much better 'coin hunting models' for many reasons. The X-Terra 30 is just a simpler unit for those who want to keep it simple. The other two X-Terra's are for those more experienced and willing to learn their detector. Have you really spent time with an X-Terra to learn it and master it?
"Sure it works and finds coins, but for the VFLEX feature it is nothing but a marketing ploy, to get you 'in' for the pound."... I think this is the second time you've referred to "pound" and it sounds like a foreign reference to a monetary value. Do you have a foreign bias about the Minelab?
"I hope the commercial facet does a better job of meeting the demands that my tax dollar pays. As a consumer the absence of official company communication is found to be rude, I hope they don't blow-off the commercial interests as they do the hobbyist's."... Nothing to comment on, mainly because it's unclear what you're trying to say.
"So as one who was once interested in a new machine and promising technology, I am inclined to steer-clear of this elephant. I am more interested in the promises of new technology from a proven manufacturer with good customer support -along with rock-solid performance."... And just which "proven manufacturer" are you interested in? Why not share those opinions with everyone, too?
As Randy (Digger) pointed out below, there are several manufacturers who have a well known name and a good track record of customer support, but not all of them offer anything that is "modern", and most of their promises of 'new technology' haven't resulted in anything earth-shattering.
"Minelab emphasises features that are not easily pinned down-like it's a big secret shrouded in new terms: how is the average consumer to know what is real science and what is marketing fluff? How about some hard facts of the users?"... yes, it would be nice if a manufacturer, ALL manufacturer's, would provide users with some honest answers. Eliminate the fluff in their catalogs and other literature, and clearly explain any new technology so as not to just hype up heir products. More facts would be nice, as well as a little more factory-direct response on an open forum.
"Only time will tell, but by then there will be new technology that is simple, superior and works: no BS."... The X-Terra technology IS simple, and the X-Terra 70, especially, offers more than the competition in the way of Ground Balance adjustment methods, and has the broadest and easiest-to-use notch segment discrimination on the market. Is it the best detector out there? No, not for a lot of folks, but for many others the X-Terra's, especially the X-T 70, doe provide ample technology and all-purpose potential.
"A salesman is interested in the sale and nothing else if he side-steps honest questions of the consumer's interests."... Sadly, too many salesmen, of detectors just like many other high-tech offerings, do not really know their product, and that leaves the consumer begging for answers and help. Thankfully, we have these forums to help wade through all the hype and bologna. I wish there was some way to require ALL dealers to be trained and knowledgeable about the metal detectors they carry and sell. Oh well, such is life.
"Kind of like getting buyer's remorse when you find out that you have been had, but the 'in for a penny and in for a pound' mentality keeps good folk from making a decision to cut their losses."... I haven't seen but a very few detectors offered today, or through the years, that really hold their value very well. They are like cars or firearms or other sports equipment. Things we buy because we want them, or like what we see or hear, or because we want to use them for enjoyment.
Nothing, however, that any manufacturer can come up with to offer the metal detecting consumer could be as bad a buy as these blasted pieces of garbage we spend so much time in front of as we peck away to convey our thoughts! Talk about "new technology" and "hype" with "non-technical answers that are understandable/" Constantly bombarded with "new and innovative features" and offering the consumer "faster clock times and downloads" and for far more than what we spend on a decent top-end metal detector, too!
Yes, wouldn't it be great if the high-tech computer industry could offer us a decent, long-lasting product that will not be phased out of production and become 'ancient' after about 90-120 days? And talk about not holding any value!! Geezzz! Yet, somehow, manufacturers of metal detection equipment seem to be able to keep making some inroads into improved products and offering at least some new features of enhanced performance, even though they have nothing close to the total dollar income of those mighty computer companies.
"I only hope Minelab has a better foot forward in the demining industry because they are getting my tax dollars to the benefit of our Troops. Good hunting. Support our Troops."... Well, I can assure you that I support our troops, and I appreciated all the support that was there when I served this great country.
And I wish you the best of success in your detecting, as well.
But I have to tell you that I didn't see any real direction in your post that was beneficial to others. No specific weakness about the Minelab X-Terra noted, other than the lack of a smaller coil and I have harped on that from the first day I started using an X-Terra 50, and have heard the promises for over a year of a smaller coil due out ... sometime. There, I will agree on a weakness.
As for comparing the X-Terra 70 to a White's M6, well, they are in a different class. Use a White's model with a closer suggested retail and I'll give you a comparison, with pros and cons each way.
As for the M6, I happen to like it. It doesn't have the adjustments of the X-Terra 70, and isn't in the same price range. I happen to also like the M6's physical packaging, nut then I am very partial to it because it is the same as the excellent White's Classic III SL and IDX Pro which have served me well for many years now.
I like the autotracking circuitry of the M6, which is the same as the MXT like most of the other electronics since it shares the MXT's basic circuitry, and while I do wish White's would have offered us a broad-range notch discrimination model, I also have to say that I usually prefer a full-range variable discrimination to "fine-tune" the disc. setting.
I liked what the X-Terra 50, and especially what the X-T 70 had to offer, and I don't doubt that I'll add another X-Terra 70 to my personal arsenal ... but it won't be until they introduce a good, smaller coil and the field results convince me that the performance is there.
Monte
and keep his negative crap off this forum. Me I got a MXT along with a bunch of other machines and you don't see me bad mouthing any of my machines and I own all the best machines and coils. Oh BTW, I think the Xterra 70 is a fine machine even without the small coil. I will be glad when it gets here cause I will buy it. Just let this guy go his way and let it be just that. Later and HH to the guys that like there Xterras as they are the ones that are qualified to talk about there machines and they are the ones that have the right to complain. I don't really see where the rest of them matter anyway. Not to me. So in closing I would like to say to the non qualified whiners, would you like some Cheese with that whine. 
HH Randy