From a collector standpoint, I'd take the G-Loc. Golden Axe is a common game, and can be handled in MAME, or you can just swap a PCB into another cab to play it. G-Loc you'll only get to play if you've got the actual game.
Of course, if you regularly have three other guys at your house, you might prefer the 4-player action on the Axe. Or maybe you just don't care for flight sims.
Plus, I notice your avatar...