I would pick CA. I actually went to a CA clinic with my dominant Appendix, and it was great for us because he was a pretty pushy horse. BUT my pony mare is sensitive and I just use very light, light pressure and cues. I don't need to be aggressive at all, and the guy that ran the clinic (wish I could remember his name, but I'll have to go look it up in my journal) said that you need to adjust the pressure for the horse, and with my mare just a *tiny* wave of the stick is all it takes and she's doing the right thing.
Parelli overall didn't work for me, but I have integrated some of his stuff and some stuff from other trainers, so it's like a smorgasbord of training stuff. I even do some Tellington Touch with my super sensitive pony to relax her.
I don't think one has ALL the answers, but I do let my friends that have first time horses use my CA DVDs because it is easy for them especially if they don't have the $ to spend on a trainer because they just blew it all on a horse, trailer, boarding, etc ... I saw something on FB about equine owners and one part said: "This is what my husband thinks I do." and it was a pic of someone burning a Benjamin. Yeah, I get that.