pick one

I will not say one is better than the other butttt:
KA has a plex and their rush classes this year were spot on. Once all their old members leave and depending on next semesters rush, they could be a decent house by next year. They would also need to be more involved on campus and make more effort for philos. Talked to a few of their guys and they have lots of events planned so watch out.
Sig Tau is new and still have a lot to improve on. They are more involved than KA on campus. They dont have many houses though. Same as KA if their rush class next year is solid they will be solid too. I hear they have a 10 man house in the cottages so look out for that.

If you're looking for a genuine response I have friends in both houses and I say the clear choice is Sig Tau. They just chartered, won greek week and will have the cottages/more houses next year. KA has improved a lot the past two years though. KA has the complex and has put serious effort in recruitment.. but Sig Tau has a great brotherhood for a new house. We played their team in softball, and like 30 dudes showed up to cheer them on while KA can barely get any presence on campus. That being said, you might find your place in either one so keep an open mind during rush.

Cancer or Heart disease? They both suck