Just my 2 cents (or maybe more than 2
)
Happygurl asked 2 questions - 1) how to know which sorority will be the best for her and 2) how to tell which sororities are strongest on campus. The two are not necessarily the same!
You can be in the "strongest" house on campus and hate every minute of it...you can be in the "weakest" sorority on campus and have the time of your life. That's when (especially rushing as a freshman) you should sit down and decide what is most important to YOU. If it helps, write out what you want, and rank what you want the most.
As far as APO, it definitely helped me that I pledged APO before ASA, just cause I knew the Greek alphabet and things like that. But only join APO or GSS if you are really interested in the service - not as a "practice run."