Hi Chef,
I really liked UCSD's MST program when I interviewed there last year. The MSTP at UCSD is anything anybody can ask for--great support (the directors are fantastic and administration seemed excellent), absolutely gorgeous research facilities, great atmosphere for grad students (i.e. nonmalignant programs). Plus, the program there seemd like it was very high priority in the medical school. The dean at USCD medical school just came from Duke, and after experiences with Sal Pizzo, he was strongly in support of expanding the MSTP. That, and the fact that the students I met with whom I just "clicked," made me very impressed overall by the program, and I strongly considered attending.
My only reservation about USCD was the medical school. Although it is in a prime location (how much more can you ask for but 10 minutes from the beach?), it had a very intense, very competitive atomsphere. Being a Californian myself, I have several friends at UCSD both in the med school and in MSTP, so I knew about this competitive and stressful atmosphere before I went. My interview there was with the Dean, and he only reinforced my fears by emphasizing the importance of grades and establishing a "hierarchy amongst your peers". So even though the students there were great and the MSTP was fantastic, I decided to turn UCSD down.
I am very happy with that choice. I am currently attending a top-5 with P/F grading, and the MSTP here is awesome too. I probably would have been happy attending UCSD as well, but I have no doubt that I made the right decision for me. Chef, you should see during the interview whether the atmosphere is right for you. Talk to students, not just students on the tour but random students too, in order to get a representative view of student opinions. Best of luck!
(P.S. I interviewed at well over 10 MD/PhD programs last year... where else do you have interveiws?)