Personally, I have not been impressed with a single parelli trained horse I have seen. All that I have seen are very disrespectful, have no idea about personal space, and just aren't pleasant to be around. Most of the people around here that do parelli are a bit off their rockers as well, and maybe just aren't doing it right. JUST MY OPINION! I also do not agree with one method, and with parelli, it confuses the crap out of me and it would be hard to combine with other methods.
Look around and see what you like best, and then see what your horse likes best. Every person and every horse is different, if everyone used the same methods to do things, it would be pretty boring. I am def a Clinton Anderson fan, but a take a bit from everyone and do what works for me.