Pros
The AAMC offers what you might expect from a substantial employer -- competitive salary & the chance to grow your professional skills. The part that's different is that we're generally rooting for each other. I typically don't have to watch my back because my colleagues are generally trying to help me be successful. I have built genuine friendships with my colleagues. When there's a problem, we generally get together and figure out how to solve it rather than focusing on who to blame. Having family with serious illness, I understand the importance/significance of teaching hospitals and producing exceptional doctors. Feeling like my job and my organization are helping to improve society and real people's lives is a pretty great feeling. If you haven't, try it sometime. :)
Cons
A number of nonprofit stereotypes apply here -- we tend to make decisions slowly and by consensus. If you're used to an aggressive, action oriented work culture, there will likely be some frustration at the pace of things. People tend to camp out in management positions (hard to give up the work life balance and amazing 10% 401k contribution) so there's not as many opportunities for promotion.