I found it a little disappointing. Obviously, I was never expecting a modern classic, but I was hoping for something with the same infectious fun and goofiness of the first film. This one takes itself a little too seriously, and has an ending a little too pat, for my tastes.
It's a bit like in X-Men 3, where at the end of the Jean Grey plotline, you kinda go "Hang on, is that it?" (it's nowhere near as disappointing a movie overall as X3 was, though)
My inner comics geek is a little sad that there were no purple-clad space giants in goofy helmets, though I can understand why that choice was made.