I used them both and I like the GT better myself as the control are better positioned, has the straight shaft for better balance, but still a bit heavy. I also feel the GT is a bit more sensitive plus you can turn off the iron mask which I never do anyway as I like to get coins next to iron even though it may false a bit more. I find that the GT will fool you a little more on iron being more sensitive. I also find if using the meter it is likely to lock into a good number on a deep target better. One more thing the GT has is a switch to have silent search if you want which I thought I would never use anyway, but have seen some cases where you have a lot of ground to cover and targets are far a few, but as soon as I start getting good target I will switch back to a threshold so I can hear those deep target that only change the threshold. On the Elite and older Sovereigns you had to take it apart and switch a jumper wire, but the GT just flip a toggle switch.
I feel the GT is the best Sovereign I have used and I used them all.