I used 90% coursesaver...mainly for chem, ochem, and physics, but I also watched the bio videos and did a lot of the QR quizzes. I also used Kaplan's 2018 OAT book for bio only, which I found useful. I made flash cards using ANKI for all of the subjects, which was VERY helpful for memorizing physics formulas, ochem reactions, and everything biology related. There are no coursesaver videos on QR or RC; they have a tool you can use to practice reading faster, but you essentially copy/paste material you've picked to read. I didn't use it at all. The other really nice thing is that all of the quiz questions have fairly detailed descriptions of the right answer and, often times, why the other answers are wrong. Overall, I was really happy with coursesaver and would recommend it to anyone. Although the other people's scores speak to how well the other videos worked as well. So I think if you put the time in, you can't go wrong. For what it's worth I scored a 350AA /370 TS