Paolini is a 19-year-old kid who managed to promote his self-published first novel well enough to get it picked up by Knopf. That does make me want him to succeed, but it's not why I bought the book (I didn't even know it at the time), and the book should be the reason for its success or failure, so I won't dwell on the author any more.
It took me a long time to read the book, not because it's a horribly long book (at 500 pages, it's not short, but the print isn't small and the prose isn't difficult), but because I'm busy with enough other things that I'm not spending much time reading, and the book has a whole lot of very short chapters, so if all I do is read a chapter before I go to sleep (which is all I managed a lot of days) it takes a lot of days. This isn't the best way to read a book, and probably has something to do with the fact that I'm having trouble forming a really clear impression of what to say about it other than describing the plot.
The book contains a lot of familiar fantasy elements and little that's really original or unusual. To some, it will seem very cliched; to others, comfortably familiar. Eragon's transformation from farm boy to epic hero comes so quickly that it's a little hard to swallow, and on the other hand, some of his ethical struggles seem unrealistically naive. But on the whole, I found him an engaging viewpoint character that I wanted to identify with (even though I occasionally wanted to smack some sense into him). The writing isn't terribly polished, but neither is it flashy or pretentious; Paolini tells the story competently, and will probably get better with practice.
This is the first book of a trilogy. It ends at a fairly reasonable point; the immediate fate of the world is not left hanging, but Eragon's future is definitely not resolved.
Overall, I can't rave about this book, but I can give it a mild recommendation. If you're looking for a fairly light, non-demanding, non-humorous heroic fantasy, it's a reasonable choice; if you want something highly original or filled with many levels of deep inner meaning, look elsewhere. I give it a 7 out of 10.