If I recall correctly (and correct me if I am in error) you last owned an earlier White's Coinmaster of some sort.
In March I wrapped up my 41st year in this great hobby and started on #42. I have been fortunate in that I have NEVER lost interest (obsession???) with this great hobby, nor have I had to get out of touch with it for any reason.
For over forty-one years I have been an avid detectorist, a dealer, a distributor, and a manufacturer's marketing rep & dealer coordinator. I have had the privilege of evaluating well over a dozen prototypes for several manufacturers through the years, and have a good working knowledge about the various popular types of equipment we have had for use in this hobby.
There are so many newcomers to the hobby today, and have been over the last 25 years, who got their start using a somewhat modern design that employs some form of motion discrimination. The bulk of this group never have owned, or even used, an earlier type of detector that was a simple VLF/TR-Disc. design, or an even simpler TR-Discriminator, or heaven forbid a very basic, non-discriminating TR or BFO type of unit.
Those who have been active in the hobby through all these decades of improvements and advancement have a much better understanding of the strengths, and WEAKNESSES, of most of today's modern, motion discriminate circuitry designs.
Think back to your earlier adventure into this hobby and the detector(s) you had and/or used. Compare them with the performance and features found on your new Matrix M6. Do YOU know what this new unit provides you with that's maybe better than your earlier unit(s)? How about understanding what it might NOT do or do as well?
From your experiences afield, you should be able to come up with a handful of questions to ask to better understand why your unit does what it does, doesn't do what you think it ought to, or how to improve the performance or your understanding of the M6.
As for the decision making required to dig or not, I have a few very basic suggestions and one overriding way to be 100% right in your decision: