What I do know:
If you're from out of state, Cal is freaking expensive. It would be equivalent to going to a private. If you're not from in state, it may not be worth the cost consdering you're getting a "public" education at the cost of a private.
In my opinion, Cal is more known for their Engineering.
What I hear:
The UC system is so overwhelmed that it is simply ridiculous. Classes are huge. You're simply one of the many. It is hard to get to know the professors ect.