rankings from someone actually not in greek life

With the frats you basically have the good ones and the bad ones. You can argue for days who's "Top Tier" or not, but really it just comes down to your not that bad. (In No Particular Order)

Good (All throw good parties, you could probably split them into a top and middle tier, but you'd rarely get the same two groups. :
Phi Sig (They're in trouble now too, not as bad as SAE, but still in some pretty hot water)
SAE (But they're getting shut down now or something)
Sig Chi
Sig Nu
Sig Ep

Bad:
Beta
DTD
Lambda
Pi Kapp

With Sororities theres definitely more of a top, middle, and lower tier. That one has some more debate around it because there's probably one or two that could go up or down depending on who you ask. (In No Particular Order)

Top (Theres always an argument on who's more attractive, Tri Delt or A Chi O, but if it came down to it and you had to decide between the two you're winning either way):
A Chi O
Tri Delt
KKG (They could go here or middle, it really just depends who you ask. Upper Class classes are upper tier, but their new classes this year are middle or lower.)

Middle (These are all really nice girls, some are attractive enough to be in A Chi O or Tri Delt, but a lot are what you expect from a Catholic School drawing in girls from around Philly, if you know what I mean):
Chi O
DG
KD
A Phi

Lower (They definitly try hard, but it's pretty easy to pick out the AGD and Pi Phi girls when you see them around campus):
AGD
Pi Phi