Do not know enough about the GMT, so I will leave that to the experts.
The Milgauss GV however, is the second best version IMO (have had two in my collection). But if I were you I would go for the latest "1:1" version instead (same price) which is more accurate overall. Like blue lume on 3,6 and 9 markers, a slightly bigger dial/ thinner bezel, and slimmer crown like the gen. I have the later one on my wrist while posting this (making the typing take twice the time - can not stop looking at it)..
/modelizer.