Be patient and wait for another week or two, when the two schools make their decisions. The decisions may eliminate some options for you and make it an easier choice.
That said, I have been to both campuses and I just helped an international student make the decision last year between the two schools. You are right that the two schools are very similar with huge classes, diverse student body with a heavy dose of Asians, and lots of research funding (but undergrads are not getting much.)
There are a few differences. I’m not familiar with biochemistry, so the comparison is not major specific.
Pro for UW:
- Better international reputation
- The campus is more traditional and grand
- Tuition for international student is a few thousand dollars less than UCSD
- Seattle is a bigger city than SD and has a more vibrant high-tech industry
- You get two seasons (cold+wet and warm+dry), ski resort and beach both are half an hour away
- Why do you say both has no school spirit? Go to a Husky Football game and experience it.
Pro for UCSD
- California sunshine
- Torrey Pines
- Nice surfing waves
- Close to theme parks (there’s no themes parks around Seattle)