I take step1 in one week and have been using both Qbank for about 1 month and I added the NMS book earlier this week. I definitely like Qbank a lot more (it is computerized and it is a lot easier to go over questions that you get wrong), however I think I definitely have learned a good amount of info from taking the NMS questions. It comes with 17 50-question practice exams and I have done 7 of them so far. My percentages are slightly higher using the NMS books (scores are more similar as well), whereas my Qbank scores have a larger range (though I'm happy to say that the range is finally decreasing). I will definitely finish Qbank (I am about 70% of the way through) and will most likely not finish the NMS book. That is totally OK with me.
Another book that has great questions is Robbin's Path Review. Excellent questions with excellent explanations. Only bad thing is that it is just path.
There is also a new online question bank that is free called usmleasy.com, but I think it is kind of lame. Lots of repeats, lot of glitches, and not many questions in 'boards-format'.
Good luck.
