Kaplan Qbank was the the best thing I used for Step 2! Doing hundreds of questions on the computer in similar format to the exam really helped me. I did almost all the questions, and when I took Step 2, I did not feel much time pressure since I was used to being timed for some sections on Qbank.
I thought Qbank was thorough, and hit on relevant topics. Read the explanations even if you got the question right-sometimes there is extra information that you did not know.
Step 2 is updated yearly and most review books can't keep up with the format of clinical questions. Qbank did a great job. I bought Qbook also, but thought Qbank was a better investment. When you take the exam, you cannot highlight and underline, etc, like you can in a book. Qbank doesn't allow you to do that so you get used to reading questions off the computer without any crutches. It also helps you get used to the hours and hours you spend staring at the computer screen during the actual exam!