I voted shitty ripoff, but only because it was the closest to what I wanted to say. I don't really look down upon it for being a ripoff since all fantasy is basically derivative of a mash-up of Tolkein, Western myths in general, some biblical lore, and rabidly bad medieval history. However, Eragon was really really shitty in the sense that the writing was god awful, even for a genre not really known for great literacy. If I remember correctly, the author was quite young when he wrote the novel and you can tell right away, the style is repetitive, the pacing is poor, he lacks a full vocabulary and his characters are paper thin. To put it simply, the author doesn't have very good taste in prose. Being young isn't really an excuse either - Terry Brooks wrote the Sword of Shannara when he was a teenager too, and although that novel wasn't exactly a modern classic at least it was much more readable than Eragon.
The following novels got even worse, what with the migration/pilgrimage led by his brother/cousin/relative (I can't remember, its been a while) being entirely tacked on and not very evocative, as well as an entirely predictable plot twist at the end of the second book (where I stopped reading). It's often not the originality of an idea that makes a book great, its the execution that matters and the author really screwed that up.
Well, I really should have known, the person that recommended Eragon to me also tried to get me to read Twilight. I'm fairly certain I only got around to reading it because we were dating at the time. For the age group Eragon targets there are so many better choices than that pile of rubbish (Pullman's His Dark Materials is by far the best fantasy for that age group).