I used ATI through my school as well, but I never really became a fan of it. When it came time to study for NCLEX, I used UWorld, and also Kaplan. I found that for the most part, I liked UWorld better. The questions seemed "harder" than Kaplan, and the rationales were so much better. Very detailed. Kaplan was good for me to assess my knowledge, but UWorld taught me what I didn't already know. UWorld is also set up very much like NCLEX, so when I sat to take the exam, it felt familiar to me.