I have to defend my little AMT...it's feelings are hurt. I have an older Backup model, the single action kind. I'll conceed that it's not the best design in the world, nor is it match quality in any respect.
It is, however, a pretty darn good belly gun that gets sweat upon a lot in a leather pocket holster, and occasionally fills up with pocket lint. I haven't had any problems with rust or failure to feed/fire anything that I've put through it, including ball, Hydra-shock, and Golden Saber rounds. I bought the clunker used about 12 years ago, and still feel that I have a decent, if not good, highly concealable "OH SHEET" piece that I am confident will go BANG when I want it to, and more importantly, with the grip safety AND thumb safety, probably won't go BANG when I DON'T want it to. It has provided a lot of comfort to me on many a traffic stop.
Is it as good as a hammerless 'Smith? On most fronts I'd say that it doesn't even come close...however...it will go places (in my clothing) that a wheel gun just plain won't.
If concealability is your ultimate goal, I wouldn't rule out an older AMT single action that has been inspected by a good, disinterested gunsmith. I can't speak for the newer double action AMTs, as I've never even held one.