I like the basic philosophy, the idea of helping the horse to understand, and the handler learning to understand the horse, but that isn't Parelli per se, its more Tom Dorrance and the other foundation trainers (of horses and of people) of the NH movement.
I have had a similar experience with the system itself to that of savvylover112, my horses just don't seem to respond to Parelli specific techniques. They usually just stare at me like I'm stupid or something

. I have personally gotten better reactions and responses from my Clinton Anderson/Chris Cox/Dennis Reis/Ken McNabb/John Lyons/whoever else is on RFD - Ryan Gingrich (shudders) + a healthy dose of critical thinking and common sense. Granted, I probably was doing something wrong, as I learned about the 7 games from a magazine article, some Googling, and a few infomercial-esqe tv shows.
I also think that a lot of mainstream tv NH trainers focus much of their time and energy on foundation training, colt starting, and rehabbing problem horses (and owners

). Because of this, it's up to the owner/handler/trainer to decide where to go when the solid foundation has been established. You can refine a foundation to kingdom come, but someday you need to decide when to level up. Dressage analogy here: Perfection at Training level, but what if you never take that leap to begin schooling at First level? I do know that some NH trainers are attempting to remedy this shortfall: Clinton Anderson has an advanced riding DVD, I think Parelli has something similar (at any rate, followers of the Parelli's have added elements of classical dressage and other disciplines to produce a well educated horse).
The long and short of my rant... Parelli ok, he gets results. His biggest faults are the sheer price of his materials (but that can be argued of several trainers), and the potential for followers to end up in a "foundation skills rut" if they do not branch out a bit (again something that can be argued of most NH tv trainers).
My biggest personal beef (getting really subjective here... I'm not at all meaning to offend), sometimes the Parelli's just rub me wrong, and almost seem condescending in the way they come across, that because I don't follow their system my horses hate me, but that is certainly just my personal opinion and perception.