First of all, if you go into this book with a bunch of arrogant predispositions and an elitist literary critic attitude, you definitely won't enjoy it. Something like Martin's Song of Ice and Fire is for you. Really, if this is your attitude, you probably lead a pretty depressed life. Anyway, some people complain that he thinks he is original but only uses the same formula as is typical for fantasy. He quite openly admits to using a formula in The Rivan Codex (where you will find that he did, in fact, put a lot of work into the belgariad). Personally, I believe that it's not the initial framework that defines a good author, it's what he does with it. David Eddings does an excellent job with it.
Now some readers choose to complain that this series is not realistic enough. First of all, the name of this genre is Fantasy, not reality. Look it up. The author is much freer to do things with mythical creatures, magic, prophecies, et cetera, while remaining "in bounds." The author who chooses to minimize such things and focus on politics and other "realistic things" isn't as original as he thinks he is. He is either medieval, or shouldn't be trying to write under the fantasy title. Enough of that.
Should you choose to have an open mind, this book contains a lot of humor, despair, mystery, and some rather strange, but humorous romances. It is a great coming-of-age story and is not in the least bit confusing. The characters are all clearly defined, and many of them play off of each other very well. Anyway, this can be one of the best series you will ever read if you allow yourself to enjoy it. Whether you do or not is up to you.