I used all three, and it worked out for me. However, I'd suggest only using KBB for the eye/ear and hormones--it's a really, really boring read. Barron's was my favorite, but Cliff's was very helpful as well. I went through Barron's 2x, studied the chapters I found most important in Cliff's 2x, and only went through KBB once. Yes, it is very time consuming; if you get it all down, though, it pays off!