Actually, Eddings Sparhawc books weren't nearly as bad as the Belgarath books. There he showed he had the ability to write characters. So, this estimation is after 19.85 Eddings books. I'd say that's enought time to decide if an author sucks or not.
Rendevous with Rama and Rama 2 (don't bother with the rest) were a very special kind of book, one that really can only appeal to a specific set of readers. They're what i call "discovery" books: characters only exist to act as tour guides to a subject (in this case the Rama artifacts). If you're not the sort who goes in for boldly going where no man has gone before (to borrow a phrase), you're not going to like them. Personally I love them (I even have the Rama2 video game!), but I understand precisely why some people wouldn't.
Me, when it comes to fantasy, I expect dense plot, careful and well thought out character development and I expect recurring characters to make genuine contributions. Jordan, Goodkind, Tolkien and Martin all have this. Eddings' Belgarath books treat characters as generic tools in Belgarath's toolkit. It makes for a bad reading experience.
I read a lot. I can generally read a thousand page novel in about 5-8hrs, depending on my interest level. When I was younger, it was more like 3-6hrs. If, like recently, I have a job that takes up lots and lots of my time, I never get to settle into that sponge-like groove that lets me do that, so its more like 10-15hrs. I have a series of bookshelves literally sagging under the weight of hundreds of books and that's just the ones I bought and haven't sold back to a used bookstore. In some cases (like Jordan, Tolkien, Goodkind, Martin and Rawn), I've read the books at least twice, usually more like four or five times each. Even an author I don't like gets a fair bit of reading before I decide that I don't like him (that's a lot of Eddings I've read, for example) enough to write more than a short blurb like "Tepper? yeah, she sucks." (incidentally, she really does).
Authors can vary immensely between books (Rawn, for instance wrote the Sunrunner books, which I think are excellent, but her Ambrai books hurt like broken glass in your jock; Orson Scott Card is another good example) so you really have to read more than just one and write off the author. I can't imagine reading Jordan's take on Conan the Barbarian and using that as a basis to read the rest of his works. Likewise, Terry Brooks: the reason I hate him so much is that he took Magic Kingdom: For Sale--Sold! (a wonderful little story) and ruined it with both sequels and his Tolkien ripoffs. Good authors make mistakes and bad authors sometimes get it right. You have to read more than one book (and sometimes more than one series) to make definitive judgement.