In my opinion, online questions are a must for preparing for step 3. The online testing format is sooo different old paper formats. It's no so much the questions themselves, it's getting in the habit of clicking through them and doing this on a timed schedule. I know two people personally who failed COMLEX 3 and neither of them used an online question bank. For USMLE step 3 I liked World and for COMLEX 3 I liked COMBANK. Unless you're a stud, I'd play it on the safe side and take some practice exams. If you do poorly on the Qbanks you can always postpone your test. Best of luck.