I am currently using ExamCrackers for G-chem and O-chem (only started reading O-chem though).
It gives a pretty good summary of all the material but there were a lot of concepts that it just glosses over that I had use my textbook in order to clarify.
I think its a good source to use as a review if you have a solid background in chem (which i definitely don't)
Any other opinions?