I didn't take the full PPI review class either, I took the $200 online review class, which I found to be a complete waste of $200. That was for my second attempt at the exam, which I did not pass.
This last go around (my third time) I simply studied on my own, every night for about 4 months. It was painful for me and my family (I have 2 very young daughters), but for me thats what it took. Lots of intensive problem solving.
Everyone's different, so the review class may be for you. But I've found for myself (and from alot of people on this board), the best way to study is to do problems, problems, and more problems.
Sample exams from PPI and NCEES, six minute solutions books, problems for the MERM... if you do all those, you'll be golden.