Vandy is becoming more diverse. However, you might find that the people in the relevant fraternities/sororities are rich, white, and preppy. As a guy if you want to have a traditional college experience you should go Greek. If you don’t then there’s no reason for you to rush.
As far as Vandy vs. BU Honors goes, I’m actually not sure if Vandy’s academic offerings are of a higher quality than BU. If you are in the honors program you should have access to small classes, good research opportunities, etc. I’d try to visit both schools if you have the opportunity.