In terms of perceived academic reputation, I would say it's UCSD> USC> UC Irvine
In terms of actual clinical training, I would say it's more like USC> UCSD=UC Irvine
UCSD is obviously well known for its research in the neurosciences, but from what I have heard, its neurology residency program is not as well-respected. I actually decided to cancel my interview there (it was offered later in the season), so I really don't have a personal experience there to share.
As for USC, I actually liked the program. Everyone from the faculty and program director to the residents seemed genuinely enthusiastic. They had strong faculty in all the subspecialties, and clinical training itself was most-likely first-rate, due to the autonomy you have and the pt base. My only issue was that it was obviously one of the busier programs, and well, I'm a bit of a slacker.
As for UC Irvine, I had mixed feelings about the program. On paper, it looked awesome. Faculty in all the major fields, and a pretty decent schedule. However, during the interview itself, I just got a bad vibe about the place. Residents did not seem too happy and some of the faculty seemed indifferent. Also talked to some med students who rotated there and they shared the same feelings.
Overall, I felt reputation meant very little in regards to how I eventually ranked the programs since I was more interested in being a clinican rather than a researcher. My recommendation to you would be to stop being blinded by reputation in looking at programs. Look at programs that will be a good fit for you, not just what some stranger (including myself) says about a program...