I have had very good experiences with the USMLE WORLD and I would rank it above kaplan believe it or not. I like the break down of the subject matters. I did about 1600 questions in that thing. I was averaging around 50-55%. I also did the kaplan qbank too. I got around 67-68% on that. so like the usmleworld says the questions are harder. I think the usmleworld questions are harder than the nbme questions (CSSA or whatever they are called). I think some of the nms questions are ridiculous and don't pertain anything to the real exam. I don't think that is the case with the usmle world. all questions on that thing is dead-on. my real step 2 however was very hard and I was so sure that I failed that I started studying for a re-take of the step 2. much to my relief i scored 211/86. i am thrilled. so my advice is that is you have time (i.e two weeks) give usmle world a go because it is legit. please post or give me a private message if you have any questions about usmle world. the thing for me is that I like to study by learning the answers and reading the explanations to practice questions that I did. I also like to supplement that by reading pertinent sections to first aid and crush step 2 to fortify my preparation.
when are you taking the exam. at what stage of preparation are you at (ie what have you done so far to prep for the exam)
good luck again