Has Rice not given you your financial aid info yet? I thought that came with acceptances (though I could be wrong).
I agree with the others that I don’t think it’s worth a lot more money to go to UCB, unless you can afford it and you strongly prefer the school. I also would be very concerned about the fact that you can’t major in what you want there.
I have a Rice grad and changing majors is a breeze (except to architecture and music). My D had friends that changed major multiple times - one switched from english to engineering. You’re not accepted into a particular major and you have a year or two before you have to declare. But even once you declare you can change by filling out a form (though you still have to meet the graduation requirements of any major you change into).
Have you visited both schools? I would say they are quite different environments. Rice is in the middle of a large city, but in a very nice residential part of town (and across the street from the worlds largest medical center). When you are on campus you do not feel like you are in a city at all. But it’s a lot smaller and less sterotypically college-townish than Berkeley. Rice has the residental college system and students often live on campus for 3 (or sometimes more) years. Off campus housing is less expensive in Houston than in Berkeley. I am familiar with both areas and like them both, but they are very different and will provide different experiences.