We caught it yesterday, and really enjoyed it as well. I thought it was much better than the first one, and like it was mentioned, the Surfer looks/is awesome in it. It is a shorter movie (about 90 minutes), but I don't know that it was necessarily a bad thing. Things seemed to keep moving, and I never got bored. Sure, it isn't perfect, but I'll say it was a fun movie to see. Oh, and its probably been said before, but if you go, stay into the credits for just a minute or so for an additional scene. Its pretty quick after the credits start, so I doubt you'd even be out of the theater yet anyways.
It would be cool to see Namor in a future installment, but I thought I read that a different studio (not Fox - Universal maybe?) has the rights to that character, so they can't include him. Who knows though, we'll see how this sequel holds up and hopefully there will be a third.