there are plenty of good shops at the resorts or near them.
Colesports at park city is a good shop, quite ritzy from the outlooks but I have a bunch of friends that work there and they are all about it and have vast knowledge about gear and whatnot.
Deep powder house is a good shop at alta.
Wasatch Touring or Wild Rose are also good shops in slc.  Wild rose has a great tune shop and does most of my tunes as well as the guys at Colesports.  Stay away from aloha sports at PC though, my bro worked there and they suck balls.