I hope this message finds cowtown in timely fashion..
I just did a Powerscore weekend course in Toronto, with the said instructor. I thought she and the course were quite helpful, actually.
I have no experience with either Testmasters material or their prep courses, so I can't offer an opinion on that - but I've been to the Princeton Review month-long course but ran away from it and instead signed up for Powerscore, a decision I think I was very smart to make. One definite truth is Powerscore's superiority of instruction & study materials, and even with a less-than-perfect instructor, I think there is much to benefit from a Powerscore course; after all, instructors are required to follow a regimen, and as long as the material is covered un-haphazardly, which was certainly done in my weekend course, I'd say it's your money's worth. Also, the instructor is quite approachable and very willing to help, which is great.
My two cents.