I think responses are slow because "quality of life" is a vague term, so: For a painter I do believe LA has a more robust and expansive arts scene, but if the choice is SoCal I'd live in North Hollywood.
The cost of living in SF proper has stifled its creative culture. And a lot, IMHO. I'd choose Oakland (anyway). It's very easy to meet other painters. I'm not one and I encountered several visual artists socially. It's cheaper to live, and to me feels more open, relaxed and intimate, maybe for that very reason--cost of living!
