Let me list the reasons that these books aren't good:
1. There is barely any original plot.
2. The characters are one-dimmensional. There isn't enough for the readers to identify with.
3. His writing is choppy, he needs to learn how to distinguish between a period and a comma.
4. He simply tells the audience that something has happened, he does not show it.
5. The characters never truly change, there is no character development.
6. He uses his book to force his beliefs upon others. (e.g. Atheism, vegetarianism, etc.)
7. His main character has barely any flaws, almost everyone in the books like him despite their personality clashes, he doesn't learn from his mitsakes, yet is praised anyway.
8. Every character is horribly steryotypical.
9. Whenever he finds something to difficult to write, he simply skips over it by having his hero black out.
I could go on and on, but I have a feeling I'd eventually run out of space.
EDIT: Oh, and if I might add this: If you think it is popular because it is on the "bestsellers" list, then you're mistaken. The bestsellers lists take only into account the number of copies ordered from the publishers by the bookstores. It does not take into account how many of the books the stores actually sell, nor does it take into account how many books are returned to the publisher.
I say night I'm living in the forest of my dream,
I know the night is not as it would seem,
I must believe in something,
So I'll make myself believe it,
That this night will never go.
Laura Branigan, Self-control

Oh, Canada...