Just to echo My Two Interfraternal Brothers, having new blood so to speak and someone who has a GPA and not being affiliated with any group should be beneficial to any Greek Organization.
One reason being, is that you may have a little more maturity under your belt.
Of course, a lot depends on the Greek Organization and the size of the group.
Many times, the biggest is not the best! Check out the Web Sites of each Organization to get a better picture. A smaller chapter on a specific campus may have a very large National across the country. Each area is stronger for each Organization.
Good luck in your quest!
Becoming a Greek will make you a better all around person!