I actually saw this with some fellow (but much younger) college students at Purdue this past weekend. I liked it, but they liked it a lot more, except for one guy who said they butchered it compared to the book. I haven't read the book, haven't read or seen Harry Potter (except I saw half of the first movie on TV), no Twilight or whatever else Hunger Games can be compared to. So in that regard, I'm a clean slate.
I thought the actors were indistinguishable in age from college students, even if they were supposed to be high school aged. I thought Woody Harrelson was really good. I thought the female lead was pretty good, but she didn't look strong enough to do some of what she did (but not nearly as bad as all the waif-fu movies you see). That said the girl in True Grit was 10x better. I thought the male lead was so-so. I thought the plot had some serious problems that my college-aged friends who had read the book explained away as the result of the book being simplistic and aimed at 13 year olds.
All in all I thought it was good but not great. From the sales numbers people are quoting, expect 2-5 sequels.