I've owned three or four explorers over the years and they never got the depth *IN MY SOIL*, which tends to be medium to high in minerals, that my GT gets on coins. Yes, I set them up different ways, dug by sound, dug the worst of the worst, and still I wasn't seeing any silver past 7 or 8". My QXT Pro did just as well on silver and copper conductors. The Explorers did get things like nickles deeper, though. Now, with the GT I'm digging coins MUCH deeper than I have with any other machine. My deepest being a v-nickle in one hole and an indian in another that were both I think about 11" deep or close to that. They both gave perfect ID and good loud audio, and this was in a spot I had worked hard with my prior Explorers. I've also dug other silvers with my GT at spots that I gridded with my Explorers and wondered how in the world I could have missed them.
Why? Well, maybe it's specific to my soil but I believe the lower number of frequences on BBS machines (but still a nice span of numbers that will hit everything from gold to silver hard) compared to FBS machines and not as high of frequencies as the FBS machines (I don't see much point in frequencies above what the highest are on the GT...more than high enough to hit hard on gold and other low conductors)....all has something to do with it. Sorry for such a poorly constructed sentence.

What I mean is that I feel the higher than needed frequencies on FBS machines to hit hard on gold do more harm than good. Perhaps they reflect off the minerals in my soil. I can say the GT runs more stable and is less finicky about sensitivity settings than my Explorers were.
The GT also gives me much more stabile ID at depth than my Explorers did and from what I've seen/used on the Etrac the GT is also much more stable in ID on a coin at depth than it too. What I don't like about the Etrac is how it compresses everything into the 12th line. Now you've got a scale of, what...0 to 50 or 0 to 60?....for the conductivity factor. In effect in a very real way you have less resolution on an Etrac than most machines on the market. The ferrous value is highly unstable on it making it pretty much useless on coins in trash or at depth. I feel I can split hairs on rings versus tabs like trash on the GT with it's much more expanded resolution in that respect (0 to 180) versus the conductivity factor on the Etrac. That alone will help your gold ring totals.
Then there is the audio. Didn't like it on my Explorers and I don't like it on the Etrac. It's much more processed on them. Not nearly as telling on targets as a good Whites like a QXT Pro in terms of length/traits. The only advantage was the multitones of the Explorer. The GT has the rich long drawn out detailed audio of a good Whites but with the extra info of multitones on a Minelab. This machine truely is the king of audio. That also means if you develop a good ear I feel you have a better chance of telling gold targets from trash on this machine than any other on the market that I've ever used or know of. If the sound is warm, round, smooth, it's going to be something good or at least round in shape. If it's harsh, tinny, hollow, bangy, jagged at the edges, etc....then it's more than likely an oddly shaped piece of trash.
Then there is the response time of the VDI display. On a GT it's tied very directly to the audio. What that means is you see what you hear, and you see that information much more instantly than it shows up on the Explorers or Etrac. There is a lag time where the audio can be saying one thing and the VDI is saying another. Not so on the Sovereign. You hear it, you see it....and it's much more stable IMO.
I've taken a lot of heat for this in the past but I'll say that in my view (others strongly disagree) the iron mask ON function of the Sovereign gives me better ability to find coins in trash than "Iron Mask" ever did on the Explorer. Have I dug coins in iron on the Explorer? Sure have, and some good ones....But in my experience and testing the GT does a better job of sounding off to the coin and ignoring the iron.
A friend owns an Etrac yet he still much prefers to use his 6000 Pro XL for ring hunting.
I've heard plenty people say (usually in private where they won't get their head cut off) that the GT is just as deep as the Etrac. One guy in this forum last year even noted that his Etrac wasn't giving stable signals at one location while his Sovereign did and as a result he made some great finds. I've heard something along those lines from others as well in the past...probably due to the ground matrix or something.
I've owned many of the machines on the market, watched or used others in the field or compared them head to head on stuff, and right now I can say I'm pretty happy using the Sovereign. About the only thing that interests me at the moment is perhaps a T2 SE or F75 LTD. Maybe an AT Pro, but I don't see myself selling off my Sovereign for any of those. If anything they'd be added to my line up for certain situations. When it comes to working worked out parks and such for old coins, hunting the beach or waiding the water for gold rings, nothing IMO compares to a GT. So long as you know this machine well and like using it the sky is the limit.