I have heard repeatedly that Powerscore is very similar to Testmasters in just about all respects, with Testmasters definitely being the better one still. But I'd say if money is a concern at all, it probably wouldn't hurt to just go with Powerscore (since it's cheaper). It seems that everyone I know of has improved immensely with either or. Also, I think having a month between the course and the test is good--that way, you have more practice time in case you need it. If you don't need it, then it'll probably leave you more confident with the techniques and relaxed by test day than coming right out of the course into the exam.