I'm using a Q bank right now, but I avoid the material I haven't covered yet. With USMLE-RX, it's easy to just select the material that you have covered, so that's what I do. I use it alongside my classes and I think it prepares me well for my tests (and I assume I am getting at least a little board prep out of it as well). I'll keep adding subjects as I go on in preclinical, so by the time I'm done with classes I should be done with the Q bank as well. Personally, I'm not going to try finishing the Q bank before finishing my classes because I know it won't stick with me well. So I'll just use one Q bank for my entire pre clinical. If you think you can get through both Rx and Kaplan and have it help you, then go ahead and do that. I think it depends on how you learn.