You bring up an interesting point about the 2nd machine. I really like the Deus "system" for lack of a better word.
I reluctantly tried a Deus lite as an alternative to another Minelab which due to the local dollar crept up to almost 2 grand with taxes. ($1,980 total)
As it turns out rather then being a compromised alternative for land, it also became my primary water machine, an unexpected bonus.
Sure the active Deus coils are expensive compared to a passive coil, but it's much cheaper then a quality water machine. (Excalibur $1,500 vs a 2nd Deus coil for around $500.)
Another consideration is the risk factor, it is highly unlikely that you will flood both the Deus coil and headphones in the water. By having a land and sea system, a spare coil or headphones can be easily substituted while the other is repaired. All your eggs aren't in one basket.
Lets also look at the fact that the Deus is more versatile in the water compared to current Minelab, just like on land.
Minelab was king of the coins, but the Deus is waaay more versatile on both targets and user configuration, land and sea. (Freshwater)
Now time will tell how well Equinox does, it would have been a great machine for me...4 or 5 years ago. However now that I have been introduced to the Deus "system" it would be hard to replace it.
Look at how the "new" XP coils work with the "old" Deus hardware. XP is updating all the time, you can just roll the new hardware (and software) through your system as you see fit. That is nicer then having to jump to a completely different platform when you want to upgrade a specific feature. This little detail is a big thing, someone had their thinking cap on.
Ironically I suppose credit could go to the Minelab Xterra series, because you could change your Freq with the coil, however it had no ability to update, Freq was lock to a specific coil, just a little ahead of it's time. Also I don't think the Xterra series was engineered seriously enough. What I mean is they had their FBS series as their "serious" machines and made the Xterra series as a more pedestrian machine. The problem with that logic is metal detecting does not have a pedestrian market. Rarely does that type of person buy a machine, if they do it ends up in a closet after a couple of outings. That is not enough to sustain a niche market lineup like that, especially when compared to the raving lunatics that buy those Garrets. Garret gets away with it because their beginner lineup includes the ATPro, it matters not to them which "Ace" you buy, they all cost the same to make.
Some have mentioned Minelab flops. I tried a GoFind 60 last night, I put it head to head with a Technetics Delta 4000. The retail price is about the same though the Delta always goes on sale. (In fact just checked it's $277 CAD this morning)
The Delta will absolutely smoke the GoFind in everything except for ID of nickle coins, which is a hollow victory in that regard too because it is a hard machine to "X". The Delta is deeper, faster and handles EMI much better. Not to mention the GoFInd frame had a lot of slop. I was hoping the GoFind would be a compact little backup for digging shallow round sounds, but it's not. For $350 it should have worked at least as good as the Xterra. Who cares about Bluetooth connectivity, the purchaser won't likely use one long enough to take advantage of such features. I certainly haven't heard any chatter about it.
So the Delta will stay as a backup/loaner for friends and family. At least if they use that I won't feel bad giving them a gimped up machine. In fact I know a guy locally who did amazing with a Delta, now I know why, it's decent enough. I kinda feel bad for him because I sold him a Etrac and I think he struggles with it, he is in that quagmire now. He did awesome with the Delta, it was easy to use, but now he's too captivated with the Etrac right now to put it down. I thought based on his Delta finds he would just light it up with the Etrac, but that's not quite the case. He's made a few decent finds with the Etrac, just in that awkward stage right now and won't read the manual. (He's silver hunting with 3 tones I think, eek!) IMO it's hard to look for silver when it sounds like a "12" on a Minelab lol. Oh well we have all been there.
All my blathering aside, this Equinox will likely be a home run for Minelab. I already feel like I would recommend it to someone who wants the best "conventional" machine for under a grand. Remember Deus Lite does not have heads up display, I wouldn't push it on newer person who wants a screen, I understand the allure of having that number there at first.
However, I would like to try one first, cause I can still taste that GoFind from last night, the Equinox could suck.