Cedars Sinai is highly competitive. It's no UCLA, but its the closest thing in southern california outside of UCSD. UC Irvine is not a top tier medicine program. Like most places in California, they are somewhat overrated by residents for location relative to their position in academics, and so they might be more competitive then you'd expect.
Cedars, for example, has a more regional name as compared to Stanford, UCSF, UCSD and UCLA. But it is still quality training in a nice area. They have some reputable faculty, but they often come to the hospital after prolific academic careers at other 'name brand' places (ie. they just got a huge cardiology guy from Hopkins). As I understand it, they get big name guys when they're in the 'I've paid my dues, now I want cash' phase of their careers, so it's a little trickier to get meaningful research. I couldn't comment on why Cedars allows for more cash, but privates do play a larger role in delivering hospital care while you're there. In the units, for example, private attendings have privileges.
With regard to UC Irvine, I have heard that residents find it difficult to locate strong advocates among faculty when applying for fellowship, so the program relies on its location as being 'just outside' of Los Angeles to get its own very strong home-grown kids, or the people looking to come back to So Cal who couldn't get past the door at the two academic places in Cali south of San Francisco.
I am on the opposite coast, however, so take these observations with a splash of salt. Just what I've heard 'by the water cooler' over the last few years.
