Actually, I didn't read the book, and still liked the movie enough - to actually be interested in the book.
No, A Serious Man is not based on a novel. It's based on a book. The Book of Job.
Finding that out after the fact made the movie even more fascinating to me. But yeah, if I'd known that going in, I would have been in the proper frame of mind even sooner - and not have found the story or characters in any way odd or annoying, since they were basically reenacting or riffing on an ancient parable.
I think critics' problems are with the Bible, not the Coen Brothers.
