In Defese of Harb
Have never met the fellow, but have studied his videos and books, including his instructor's manual.
The PSIA is very large, with a wide array of skill levels and different techniques used by its 30,000 or so instructors. I know a number of these people. Most are sincere and really try to teach well, given that most of their instruction must be directed toward untrained and unprepared beginners who are using lousy rental gear. Not an easy thing for any teacher in any discipline. One big strength--the PSIA is everywhere and available at a modest fee. Two big weaknesses--elite attitude by some that demeans students and different techniques advocated by different instructors.
Harb with his PMTS has presented a viable, effective and learnable alternative that has several advantages. He stresses that the key problem for most skiers who cannot progress is improper alignment and weak transitioning skills. Regarding the transition, he emphasizes that early edge engagement by moving your CM is a central step to advanced and expert skiing.
Take a look at this WC skier from Madagascar. From my POV, his weakness is his transition and inability to engage his edge early above the fall line. The belly of his turn is way too low. He is jumping from side-to-side, throwing his body in the process and sliding his tails, not "tipping" or "inclining" like he should. He could use PMTS.http://youtube.com/watch?v=m51Fg6Hv2xM
Contrast him with Hans Knauss: http://youcanski.com/video/knauss_gs2.m1v
Maybe most importantly, Harb has provided a defined technique with definite steps that enables his instructors to make clear and accurate assessment of what a skier needs to work on. Even if you don't go to one of his camps, you can self-teach and self-diagnose.