I haven't skied the Prophets but I do own MSP's and here are my thoughts:
- They absolutely rule all mtn, from ice to pow. I've skied them on ice-rink boilerplate after freezing rain at Whistler as well as a few feet of crud and they're awesome at both. Ice performance really impressed me actually, on any other twin I would have been in misery.
- The ski is very stiff all over. I love stiff skis so this wasn't a problem for me BUT they are less playful than a softer ski. I didn't feel like going and jumping around on them, more just charging, skiing fast. Because of this they can be tiring to ski until your legs get used to them, then they're awesome.
- They're soooo stable in the air and generally on the snow. I've landed on one leg off balance a few times and the stability of the ski has saved me. They just won't tip over, and they won't hook when you don't want to.
- The ski has a bigger turning radius than most 'park skis', meaning that they carve GS-style turns, and they also hold an amazing edge. HOWEVER, after a week on these skis I found (once I'd found the sweetspot of the sidecut) I could also carve small turns, and flick them edge to edge really quick.
- The ski has a lot of still tail so you don't want to get backseat on them going quick edge to edge or they'll kick your arse. Once this has happened you'll never do it again.
To sum up: I fucking love these skis. I've skied a whole lot of twins in my time (PE's, Seths, Karmas, Ar5's, Elizabeths) and these are by far my favorite skis for all-around ripping. It'll take you about a week of solid skiing to really feel you are commanding the ski, then it'll do whatever you want and you'll love them. All this talk is making me want to ski them now!
A final word of warning - I've skied the MSP at centre mount and they were SHIT. Very skittish and didn't want to initiate a turn. I recommend mounting them 2cm back from Freeride for all-over performance. That seems to be the sweet spot of the ski, and it'll be better for all mtn/pow while still being decent for park (the ski has a fuckload of tail, trust me).