I used USMLE Rx for Step II. I went through USMLE World first all the way through on tutor mode reading all the explanations really well through it. After I finished World (61% avg), I ordered USMLE Rx. I approached Rx as more diagnostic and wouldn't read all the explanations all the way through. I timed most of my tests and went through the explanations afterward, but almost never reading all of it. I average 76% at the end of USMLE Rx. Actual Step II score ended up being 236. For the record, I only used the question banks to study and didn't use any books except for very occasional reference. Hope this helps you.