I've had to fix a Parelli-trained horse, so of course, I'm not a huge fan of his. My old gelding was trained using Parelli (not very well-executed Parelli, mind you, but still Parelli) and he was more of a handful as a trained six-year-old than my unhandled two-year-old stud colt when I bought him. Retrained my old gelding literally from the ground up using common sense and a little bit of CA and ended up with an eight-year-old that we used as a bareback lesson horse in a french link snaffle (his old owners said he couldn't be ridden in anything but a twisted wire snaffle, direct reined
, with spurs, and his head tied down to his chest).
I have used a lot of CA's methods on my coming 3yo and they've worked really well.