Yes the GMT is far more useful if you travel across different time zones. But even if you don't, the GMT with its green hand is far more unique than the Sub.
Everybody seems to be wearing Subs these days ... and nodody really dives with it so the depth rating & dive bezel are pretty much useless.
Having said that, your 16610 being the previous reference, does give a nicer almost-vintage look & feel.
Really depends on how much you're getting out of the trade. Just my 2 cents