I frequently read things I don't think I'll like, so that rating system wouldn't be fair for the books.
4 - Made me think and sticks with me for a while. This is the highest initial score I'll give. If I'm still thinking about it six months later, I'll give it a 5.
3 - It was okay, but lacked weight or quality of writing.
2 - I didn't like the message nor the presentation, nor do I think it is a useful way to spend my time.
1 - Badly written, bad ideas, not thought provoking. But I have to think, is that because I didn't like it, or it's not what I like. Am I being fair?