I like AA50 better. We actually succeeded with a Kill Japan First strategy in the 1941 scenario, which I didn’t initially think was possible, which made for an exciting pacific game, for once. I love the inclusion of Italy, and the way research is conducted means that people buy it and inevitably a couple players will get technologies, which makes every game different.
AA50 is a sight better than Revised in my opinion, and is worth the money. I can’t think of any changes from Revised to AA50 that I wouldn’t consider an improvement.