Rankings do not matter. It's an arbitrary title. The only case it will matter is funding and major differences in teaching material or pedagogy. For example, a community college will be different from a UC. However, the creative studies department (CCS) is much more different in pedagogy compared to the default humanities coursework. Every college is different. The department differences will be most important if you are considering academic reasons for moving.

What really matters is how you will utilize your presence at University. If you are an incoming student looking to party, then decide on that. If you are legitimately interested in the field you are studied, then read on the faculty pages and available coursework for undergraduate. Consider facilities available, the career path you'd like to take, research opportunities, and where you can manage the best you.

Consider posting your considered major, along with your backups so we can help you further. Maybe contact the major advisers at UCSB or UCSD present as well, but do not waste their time. Also, as students from UCSB we can not give you a valuable comparison on UCSD, know your audience.