I've known two people who used them (one with a GSD mix, the other with an Aussie) and both dogs were fried by that training program. Specifically, they were often "corrected" with the E-collar for legitimate mistakes--the dog didn't know what was being asked, and the owner was instructed to shock them anyway. I believe there is a place for E-collars in training, but there is absolutely no reason to use them to "reinforce" basic training as was done with these two dogs.
I have also heard significant complaints about their business model, which is (from what I've heard) geared towards making money, not turning out competent dog trainers. It is a franchise system and I've heard it likened to the "Mary Kay" of dog training. Nothing wrong with making money, but what it means for you is that you might go to a Sit Means Sit-certified trainer who is great, but you go down the street to another one and they're an abusive idiot who shouldn't even be allowed in the same room as a dog, and just kept that under wraps enough at the training school to pass. It's the same problem you get with other franchises (like Petsmart and Petco), but with the added risk of easily-misused E-collars being used as a staple of the training.
It might also help if you told a bit about what your training goals are. Are you looking for basic obedience, performance, etc.? That might also color the advice you get, as one of the major objections I (and many others) have to them is the use of E-collars so early in the training...which wouldn't apply if you're looking at Schutzhund training or something like that.
The rowdy dogs:
Hector-2 y/o GSD (mix?) rescue
Scooter-12 y/o ACD/Border Collie mix
Bandit-8 y/o ACD
Wooby-14 y/o ACD, the only other lady!