Slim pickings here in So Cal. Also in San Diego. We pay for the very good weather. Mt. High is ok ... but wouldn't be my first choice. But it's easiest to get to. Bear/Summit is small. 250 acres each or so. Mt. high is tiny, very small, at least the main resort. East resort is longer but still not all that great.
It's ok, but me and my crew make trips each year to real resorts. Denver, Tahoe, etc. Going to Seattle in two weeks.
I have not yet been to Mammoth, but that's the mountain to go to if you are driving. It's a long drive. 7-8 hours. All of my friends who have gone to Squaw, Breck, Keystone, Canyons, Park City, still like Mammoth the best. They love the other places (especially Squaw) but they like Mammoth for the way the mountain is setup.
We are all inbound riders so those opinions are talking about that. No sidecountry stuff.
The best time to visit is after it snows. It is icy and slushy especially during spring. But we just went this past Sunday (Snow Summit) and it was nice. Snowed lightly for two days so it was soft all around, 6"-12" at the top. Hey, that's not bad for So Cal!
So Cal is for park.