what makes a great sorority

It depends on your perspective. from a frat guy, chapters are good if they have hot girls, party hard, and mix a lot.
From another sorority, it's hard to every look good. Even though on an individual level sorority girls are all friends with each other (i.e. friend groups span many different chapters) there will still be broad stereotypes and ESPECIALLY on this site everyone tries to put everyone down.
From a non-greek perspective, it's also hard to have a good rep. Regardless of how much service you do, how much money you raise, people will still see greek life as a cop out for partying.
Personally, I think sisterhood defines the best chapters. PNMs inevitably join sororities based on appearances (because how much can you really tell during 4 days of talking with no more than 20 girls..). But once you get in, you see. We have some great chapters that have really close sisterhoods, like they are all supportive of each other and really do genuinely like each other.
It depends on what you want. If you want to be part of the hot group, there are a number of chapters to choose from. If you want to be part of a strong sisterhood, there are a number of chapters to choose from. If you want to do a lot of service there are a number of chapters to choose from. You just have to try to find the best mix of all of those things for yourself!

That was the long answer. The short answer is.... Eager to put out..