I used Blueprints, Swanson's Family Practice Review, and NMS USMLE Step II question book for both COMLEX and USMLE. I'm happy to report that I did fairly well on both. Several of my classmates used Prescription for the Boards and found it quite useful. Good luck!
NMS questions for Step II is the gold standard.
Everyone in my class swore by Secrets for Step II.
Evidently "Crush the Boards" is written by the
same folks and has the same info, but in a
different format. I looked at Crush, but liked
Prescription better. I did NMS, of course.
Between doing the rotations and studying for the
shelves and doing NMS, I don't know that anything
else really mattered much. In the end, I would
say NMS questions, Crush-Prescription-or Secrets,
and a good third year, and you'll do fine. I
scored in the upper 230's if it matters.