I just saw it last night and really enjoyed it. Animated films seem to be the only "mainstream" films I enjoy nowadays.
I thought the animation was incredibly beautiful and sophisticated ( I especially like the more "traditional" "Chinesese" style sections at the beginning and the end).
Some excellent lines as well , funny and moving in parts too.
I am not a big fan of Jack Black but this is definitely THE role for him IMO ! He truly IS the Awesome fat Panda.
I don't think there was one shot I would not have been happy to have as a still in my home.
Like most animated films though I can't help but feel most kids will completely miss about 80% of the humour in it.