Replying to Questions about Boots

I just hit up the search bar and I got a little info, but I was wondering for all practical purposes, how is a park boot (like an SPK for example) going to hold up on big mountain?  I have tried on a bunch of boots, and I am kind of strapped for cash, so the really comfortable and well priced boots are appealing right now.  I won't be dropping 100 foot cliffs, just doing general all around skiing, half park half everything else.  Any help would be sick.