Thanks bud, I am very lucky to have acquired 2 great vintage pieces. It's cool to have the 2 different animals, as it were, even though they share a lot of DNA! The gilt dial on the 1675 is to die for, even if I say so myself. But I also love the matte dial and no-nonsense tool qualities of the 1680. Well said about the all-rounder qualities of the 1675, too - I quite agree. Very versatile. I love both, but if I absolutely HAD to choose, I think I'd keep the GMT.