I am about 3/4 of the way finished with the Qbank and have found it to be very helpful and similar to what I am used to seeing on COMLEX exams. The site was recommended to me by a friend who had failed COMLEX level 3 and thought the COMBANK stuff was very similar to what he had seen on the previous two tests. In fact, he even recognized a couple of the questions. He ended up getting 59% on COMBANK and then got an 82 (two-digit) on COMLEX.
Like I said, I take my test in two weeks so I'll know first-hand then but I've been really happy and would highly recommend the question bank. The medical ethics and OMM sections are especially good. Apparently they will refund your subscription fee if you don't pass the test too.