socal

Well, I see you've posted this on a couple of different school boards, but I'll entertain the question anyway on the sorority side.

1 - It can totally depend by school. Some regionally strong organizations can be weak at any given school. That's just how it works.

2- You've excluded several schools that have large and growing Greek systems, but may have a weaker reputation for academics (Chapman, Long Beach, LMU, USD, Cal State Fullerton). You also excluded UCSB, which should be in your list considering you included UCSD and UCI.

Taking into account just the schools you listed:
DG is at all of them, and top tier at four campuses.
Pi Phi is at all schools, and is near-top or top at three.
Alpha Phi is at four, and near-top or top at three.
Kappa is at three, and is top tier at all of those.
Theta is at four and middle to top at most of them.
Gamma Phi is at four, and middle to lower top at all.
Tri Delta is at four, but all over the place in rankings.
Alpha Chi is at all the schools, but only good at one.

If you were to widen your list of schools to those I mentioned, Alpha Phi and DG would be the clear winners. Gamma Phi and Alpha Chi also do pretty well at those second-tier schools.