I finished the Orgo 1001. I don't know how good it is, but repetition really helped me a lot because I'm too lazy to memorize stuff. (Yeah you read right, I'd rather do 1001 questions than memorize) Anyway, after doing the 1001 book my weakest subject is now one the strongest. So I definitely think it's worth doing if you're not very confident about it. I'd imagine the gchem 1001 is similarly useful as well.