All are killer watches with my favorite complications. One of them might be in my future this year... thoughts please!
Sinn 144 St Diapal:
+200m water resistance
+perfect form factor (small lug to lug, only 14.5mm thick)
+hideable 12 hr GMT hand to clean up dial when not needed
-hefty premium for Diapal
-service only through Sinn or RGM
-top grade 7750, not chronometer certified (but still north of $3k)
+I like Bremont's hardened case and trip-tik
+Bremont has outstanding customer service
+Love the look of the ZT/51 but unsure if the silver subdials overpower the rest of the watch. In some pictures they appear brighter than the hands. The regular ZT looks great too.
-Bremont has had a run of poor quality control. Don't want to have to use the outstanding customer service.
-A little thick
Dodane Type 21: (not a GMT but some variants have a GMT bezel which works for me)
+Excellent build quality
+Actual military heritage
-Modular chrono (unsure if the additional power demands limit the life of the base movement)... slop when setting time.
-Not much of a support network
-Bracelet isn't easily available
I'd throw in the Dodane Type 23 since that's even cleaner, but a fellow forum member told me the lug to lug killed it for his 6.5" wrist (same size as me). They do look pretty big and stick out in almost every picture I've seen.
Let's pretend they all cost exactly the same and I don't care about how much of a hit they'll take on the used market. They'll all be awful on the used market...