i dont live out there but ive been out there alot, and they both are really differnt but can really be the same. snowbird seems to do more grooming and yea has a better park, but dont go up little cottonwood looking to ski a park.  i prefer alta even though on a powder day it attracts more people, but then again i havent been on snowbird on a powder day, ive only been when its been warm and sunny, which is prob a better time to go to snowbird. its your choice and all snow dependent tho