I'm going to be boring, too, and say I thought it was decent, but not spectacular.
What really carried the movie was some of the acting. Morgan and Haley were superb, and Wilson also deserves kudos. Crudup I'm torn on, but I'm giving him the benefit of the doubt considering how hard Manhatten would be to play. I wasn't a fan of Ozy or Silk Spectre, though. Ozy was just terrible all around. His look and acting was just. . .awful. And Spectre had the look (She was damn hot in the movie), but just fell flat.
I was fine with the extra violence, but I felt the sex scene was kind of ridiculous and gratuitous. I also LOVED the opening sequence, however.
I HATED the ending, though. For numerous reasons. One was making Manhatten the threat. Wouldn't the Russians still blame America for harboring and creating Manhatten in the first place, regardless of him attacking America? That really stuck out in my mind. I also was pissed that Manhatten didn't tell Ozy that the peace, ultimately, wouldn't last. That was Ozy getting defeated. No, instead, he won. And it was stupid.
However, I also hated the ending in the book, as I felt it was overblown, cheesy and completely ridiculous. I've just come to the conclusion that Ozymandias' plot was so ludicrous that it wouldn't have worked if it wasn't a comic/movie. So, I just ignore the ending.
I did like the addition of Nite Owl to the Manhatten-Rorschach exchange, though. It added emotion to that scene and that's exactly how Nite Owl would have reacted.