Interesting how many people are naming their own GLOs...
I will follow suit and say that AEPhi is the most underrated sorority at my school. We do just as much as the other four, raise just as much $ for our philanthropies, have just as strong an academic program (I think my chapter has always exceeded all-sorority GPA and has had the highest sorority GPA for a couple of semesters), have a strong sisterhood... but we're small. We started from a small local sorority - there were only 10 of us when we were colonized. The chapter has since grown to around 30-35. But the other sororities have around 90-100 members, so PNMs see one sorority glaringly smaller than the others, think something's wrong with us, and cut us at the first opportunity.
Back when we were a local, it was even worse. We were derided for not being a "real" (read: national) sorority. We got this from independents, PNMs, members of other sororities (how panhellenic of them
) and even from our Greek Life Advisor!
</bitch-session>
For the fraternities, I'd say probably ZBT. Great guys, but their house is very far from campus and I think that hurts their visibility, especially during rush ("why should I live all the way out there and have to drive in every day when I can live in a fraternity house right on campus?")