University of California is the system, not a single school. The UCs include Berkeley, Los Angeles, San Diego, Santa Barbara, Irvine, Davis, Riverside, Merced, and the graduate-only San Francisco. Each campus has distinct character, academic strengths, and culture. Berkeley is the prestige flagship; Merced is the ambitious newcomer; San Diego is rising fast. You need to choose among campuses, not just apply to "UC."
Systemwide, UCs are world-class research institutions with strong undergraduate education, though resources and attention vary by campus. In-state tuition is significantly cheaper than out-of-state, which is a real advantage for California students. All offer strong financial aid, research access, and strong alumni networks.
If you're California-based and want a top-tier public research university, explore campuses individually. Berkeley and San Diego are most prestigious; Merced is emerging. Cost-to-value depends on major and campus. Don't just think "I want UC"; think about which UC culture and academic environment matches your learning style and goals.