I think the Canyons is the worst of the Park City resorts. I've been there many times and have tried to like it but it's the traversing from hill to hill that is a time and energy waster.

However, I think Park City is great bang-for-the-buck.
I can get a cheap flight from LA, get a free 1/2 lift ticket when I arrive and spend the weekend in Salt Lake for under $100/night at a nice Marriott, Hilton, etc.

I like Mammoth but the drive time and lodging expense actually ends up costing me more in time and $

Have to say that I made two trips to Whistler and am not a fan. It feels like they are long runs but once you get half way down the mountain below the clouds, the quality of the snow changes dramatically.