I saw the movie last night, and read all three books a few months ago. I'd give the movie 3 stars out of 5.
Caution spoilers:
If you've already read the books, you'll probably be able to fill in the gaps in the film and enjoy it to some degree. If not, I can see how some people might be confused or disappointed; some key elements of the plot are missing.
I really disliked the shaky / blurred camera work and lack of sound in some key action scenes. Fundamentally, the Hunger Games books are about the effect of violence on young people and those around them. That aspect of the story is almost completely lost in the movie. It feels like it was censored by the Capitol to avoid disturbing us in the Districts.
I didn't care for the way the Katniss and Peeta characters were directed in many scenes. They were so flat and down that the movie has a bit of a depressing feel to it. The depth and range of emotions that comes through in the book was completely lost. The supporting cast did better, but even there, depth was missing. In fact, the whole movie generally felt flat.
Character development was weak all around, but especially with the tributes. CGI was weak, and particularly bad with the muttations at the end (missing the huge shock factor for Katniss), and the "girl on fire" could have been much more dramatic. They should have skipped all of the game control room scenes, and Seneca should have had a much smaller role (as in the book).
There were a couple of good, powerful scenes (such as the three-finger salutes). But in the end, I left the theater feeling somewhat let down.