I don't think high sales make these books good. McDonalds is a huge corporation, but that doesn't mean the food is good or good for you. Twilight is poorly written, and contains pretty twisted depictions of relationships. While I do understand the idea behind don't like, don't read, it is impossible to form a valid opinion on the books before reading them. After reading them, I think it is valid to critique them.
And I'll say to that, if they suck, you stop after the first one. You don't go back for the next 3 or go to the next 3 movies. If you do, and you continue to say they suck, then there's something wrong with you, not the books/movies.
ETA: Renata is a beautiful name. I can see a beautiful little long haired girl with that name.