My wife and I have only stayed at values, and tbh, will probably only stay at values. We just don't see the point in spending the extra money, when the room is only used for showering and sleeping.
For our trip in October, we decided to stay at AoA, just because it was new. In '09, we both really enjoyed Pop. Then last year ASMo was fun also. We were in a Mighty Ducks themed room, so it was just as quick for us to go to the ASSp food court. To me, there is no real difference in any of the All-Stars resorts.
Once we have stayed in AoA, I wil be able to make a better judgement call as to which ones I like better. But at this point, I enjoy the scenery at Pop best.