from what i've heard, they weren't seeing eye to eye and it was pretty serious, so he left.  not really a bad thing, if you ask me- i like what PBP did with his segment a lot more than what MSP has done.  keep in mind that while he's a big mountain guy at heart, he still loves booters and such.  PBP is are the forefront of the ski movie business right now and going with them is a great way for him to continue making sick segments.