I did a 4 week surg path rotation at UCI and just interviewed there. Multiple interviewers actually noted that they were not in the same class as other places I will interview (BWH, JHU, UCSF, Stanford, UCLA, UW). So, if you are going for reputation, you would probably be better served by going somewhere else.
That being said, I really liked my rotation there and I think it would be a very good residency program. Interviewers noted that reputation does not always agree with results, and I agree. Teaching is emphasized there a lot more than other programs I have seen/heard about. Interviewers spent a lot of time talking about improvements the program will be making and I believed most of them. They also intend to be adding a variety of fellowships, which has been a weak area there. Number of specimens is pretty low, but having the Zhao Cancer Center means a lot of specimens are pretty good. I also like the experience of rotating through 3 very different hospitals--UCIMC, Long Beach VA, LBMMC (community experience). Some people find this to be a hassle.
Residents are cool, fun to work with although by spending four weeks there I could identify one or two problem personalities.
Interview itself was pretty low key and I imagine they are aware of their reputation and will spend a lot of time selling themselves to any decent candidate.
ddx - interesting that you heard that about UCI. On my interviews/rotations so far, attendings/residents have badmouthed Cedars-Sinai saying that "you will just cut meat" the whole time you are there. I don't know how accurately any of them know the real situation, however. I dropped my interview there based on the fact that I am looking for a more academic program, not because of those comments. But I think I heard more comments about Cedars-Sinai than UCI whilst talking to residents/attendings over the last couple of months. Always take everything with a grain of salt, I guess.