who to rush?

In alphabetical order:
ATO is irrelevant
Kappa Sig is too small
Lambda Chi is too big
Pi Kapp is most athletic
Sigma Pi parties the hardest
TKE is gentlemen
Phi Delt is best looking

First of all, don't say thanks brothers cuz you're not one yet and you can be brothers with all organizations either. In response to the reply above, you are an idiot- first of all the list you posted isn't even in alphabetical order and I think you also have your descriptions sorted incorrectly. From a real Greek member's perspective, here is what I think:

Correct Alphabetical Order:
ATO- very athletic and essentially the meathead fraternity, very much into the "bro" mentality and working out over anything else
Kappa Sig- large chapter and very well known but have many issues internally that they need to fix, and regularly are feuding with other chapters
Lambda Chi- struggling to maintain numbers, and for the most part are relatively low key and not as involved on campus as other chapters, very "fratty"
Phi Delt- new, young, yet immature and are trying to charter, they are still trying to figure out who they are and where they fit it among the Greeks
Pi Kapp- mysfit or underdog organization that for some reason are on the rise, very gradual growth, involved but often times are forgotten about
Sigma Pi- large and at times recruit for quantity over quality, very pretentious but usually win every contest on campus, and they are a very diverse chapter
TKE- they are slowly trying to make a better name for themselves, very fun and social but not too involved and struggle with recruitment every semester

These are honest opinions!