So I saw it. My review follows (minor slight spoliers but nothing that you wouldn't already know from the trailer).
Let me say first that I thought it was excellent. Of the movies I've seen this year so far, this is probably the best non-comedy that I've seen.
The story and characters are definately what drives this thing. I do feel that parts of that felt rushed, but what I suspect has happened is they wanted to bring to conclusion a story arc that really should have been seasons long and not tied up so quickly. That said, the movie pulls things off excellently. It was fast, very fast, but not stupid and it didn't spend time explaining things that shouldn't need to be explained (as many movies waste time doing). Everything was important to the plot. A few of the characters were a bit left out...this seems to happen in ensemble movies. Kaylee and Mal are my favorites and while Mal got plenty of screen time, Kaylee got less. But that happens.
CGI was flawless. Excellently executed and the space battle I think was even better than this years Star Wars foray into that area. Although the battle was short, and we didn't get to see nearly as much as I wanted, it was still fantastically done. What I do miss is the track, pan, and zoom effect that was present in the shows CGI (and also in BSG). I think this may not have worked as well on the film as it may have made people motion sick so I think I'll forgive that...
Best parts was that it was fun. I've had a really bad couple of days and I still laughed through a good number of parts and I was overall entertained.
ALSO...the villan...best I've seen in a while. You can actually identify with why he is doing what he's doing. He's not just The Bad Guy(TM).