Alta if I'm making the drive, Park City if I'm paying (season pass for the family and close to home), Deer Valley if someone else is paying- the tourists stay on the runs leaving all the fresh trees for locals, so nice of them.
Tonys grove without a doubt, it has allot less idiots around then up in Monte and it is too far for me to go to anyplace decent to the south... but then again my two parabolic skis are pushed by a 36" track and a 600cc motor...As for strapping sticks on my feet and paying to get carried up to the top of the mountain.. Nah thats not for me..
I really enjoy Deer Valley Resort. I like that I can leave my skiis there for free and not have to haul them there every time I ski. I also enjoy the great skiing and food. I rarely ski any where else. There is a reason Ski Magazine keeps rating it #1.
Brighton definitely - I started riding there because they had decent trails for night riding. Quickly got hooked on the place because of the wide variety of interesting terrain.
I can't stand riding the groomies with all the other cattle - prefer playing in the trees, getting some air, and going home tired and sore. Brighton is the best I've found for playtime.
For me it depends on several things...
1. Are you a skier and don't want snowboarders? - Alta
2. Big Mountain, lots of snow? - Well, any really, but I still say Alta
3. Big jumps and a fun Terrain Park? - Brighton
4. Silky smooth groomed trails? - Deer Valley
5. Night Skiing? Brighton, Park City
I've never skied Snowbird, or the Canyon's, or anywhere else in Utah other than the Cottonwood Canyons and Park City area, so my opinion's are incomplete at best, but that's my $.02.