UCI vs UCSD

I got into UCI as a Biological Sciences major and as a Biochem major at UCSD. I visited both campuses, but I’m still unsure about where I want to spend the next 4 years of my life. I’m leaning more toward UCSD because it’s highly ranked in the science field. However, I’m afraid that I won’t be able to handle the academic rigor that it demands along with the competition. I understand that it won’t be nearly as easy at UCI, but I enjoyed the friendly social atmosphere there when I visited. Also, many of my high school friends are going there, so it’s always nice to have a support system. What are some pros and cons of attending each school?