Hi Chris,
I am graduating from UCSB Materials this year and going to Caltech for a postdoc, so... my perspective:
Either place you go, you probably won't get much done in regards to research the first two years or so (I tired but did not get much done). Do not worry about that. The classes are possibly less rigorous at UCSB, but still time-consuming. The most important thing is to join a research group that you like (Advisor, the work, and your labmates). Bummer you didn't hear positively from the group you were interested in at Caltech, the same thing happened to me when deciding (I went to the 'other' school). My advice on that is, be persistent. I actually have the same interests as you so I know the groups that you are probably thinking about joining (at least at SB). I can tell you that you will have all the tools you need at UCSB, and that physically having access to them is very easy. We have had people leave our group and go to other great schools and complain about access to equipment.
If you have questions you think I can answer, just message me on here. Good luck with your decision.