First Mark Kermode gave it a fairly flat review, touting it as all surface and no depth and failing to capture what made it so good as a comic. (Kermodes Radio 5 podcast page, direct download link o Watchmen review here).
Then I read what Pádraig Ó Méalóid had to say on the film. Pádraig’s a major expert on all things Moore-related and looks at it with first hand knowledge of what Alan Moore thinks of the whole affair and has put some much needed historical perspective into the review. But essentially he and Kermode are saying much the same thing.
From Pádraig's review:
It looks a lot like the original Watchmen book, but has none of its grace, or beauty, or subtlety, or sinuously beautiful timing. Watchmen is the most perfect graphic novel there is, and a huge amount of work went into making it that way, and attempting to streamline that for the big screen was never going to work. Alan Moore said it was unfilmable, and I have seen that he was completely right.
I'll see it eventually, but after those two reviews I can't see myself heading off to York to see it. I think it's one that I can wait a little while to see when it comes to Pocklington Arts Centre.