I was a really big fan of Eragon when it first came out and I can still (sort of) enjoy it. Although the last time I read it, I ended up writing all over it little editorial comments. I did and do like the fantasy world that Paolini introduces. Granted it's a fairly generic world, but it's presented consistently and vividly and that's one of my favorite things (besides dragons!). By Brisingr, though, I began getting a little tired of Eragon. He didn't seem to change a whole lot besides getting some fighting ability. The book overall was a slow read for me. Perhaps I was just in a reading slump or I wasn't really into fantasy at the time, but the story seemed to move more slowly.
I believe that there is nothing really wrong with this book, and it successfully carries on the plot of the Inheritance cycle. As far as fantasy goes, it is a good read, and the language is not difficult to follow. If you don't mind the main character and you are a fan of dragons, you'll love it.