one of my most defining college experiences. For better or worse. I'll try to keep it focused on how its applicable to a career/applying to grad school
Pros: Personally, it's helped me develop a set of social skills that will be very practical in the real-world: how to manage a 100 man fraternity (how to lead as a doctor), interact w/ new rushees/new people (interact with a diverse patient population), how to deal with administration/pledge educator (how to deal with other authoritative figures), & etc. Also, I was able to work my fraternity experience into a very positive frame. Although it's barely mentioned in my work resume, I will definitely mention it in my med school application when I apply next cycle.
Cons:
1) It's definitely hindered my academic performance. The jist of the dilemma I always faced: party with close friends & girls or study for a midterm? party with close friends and girls. (hope that didn't sound too d*uchey).
2) Peers/professors and I'm sure adcoms too will have a tendency to typecast you in a certain frame. It's easy to fall victim to it. It'll be your job to "break the mold" Despite these barriers, it's still possible to achieve in an academic environment.
long story short, just do it! The only real piece of advice that I wish I got on greek life is this: don't let greek life affect your gpa & make ur greek experience is a positive one.