Well, I was a bit lazy and did the practice exam around 11 pm the night before the real Step II just to remember how to use the computer program. I got around 90% of 150 right, but did all 150 questions in about 35 minutes. This was after all my studying so I'll bet I would have done worse before I did the hard core cramming. Took Step 2 on Dec 4, 2001 and scored a 259. I also didn't think the questions got harder as I took the exam like some people so I don't think they implemented that system where you get progressively easier or harder questions the better or worse you do, although I was exhausted after the exam. The questions are much longer than the Step I exam too and I did 3 hours straight then 10 minute break, 2 hours then lunch and then for the last 3 sections I took a break in between because I was just dying trying to keep focused. You get to the point where you just don't care anymore but I did my best to stay focused.
The questions on the practice test seemed to be a bit easier than the actual exam but it's a lot less stressful when you're doing those and knowing that they don't really count so others may have a different opinion on this.
Good luck. I thought the exam was easier (although the questions were much longer) than Step I, but I also worked a lot harder and studied more in my clinical years than I did those first couple years of medical school.