I came across his books just a few days ago and I'm considering purchase. Has anyone tried them? If yes, what did you think about them?
I've seen a few good things said about him on various GMAT forums. His approach seems focused on teaching you how to THINK mathematically (I found it very interesting when he said quant and verbal test the same thinking skills). This seems very different from the strategy employed by all major prep companies, which is usually to make you feel familiar with various GMAT question type variants by bombarding you with thousands of questions.