i've talked to a rep of powderpak because i was interested in making my own backyard setup.
from what i can tell, powderpak doesn't need water. and the only thing that might be a problem is it gets dirty really easily and is semi-hard to clean off. especially if you get it in white.
the msnow actually looks a lot better. and i don't think it would fuck up your skis at all. it looks like bendable plastic, plus there is room in between each spike so it is easier to clean.
the only thing is msnow is way more expensive. at 6.95 a foot plus 1.00 shipping, it'd get pricey real fast.
it really comes down to how much you want to pay, i'd say.
if you have money, get msnow
Salomon TwentyTwelves, but i still love Line Skis.