I was down to those two schools and chose GW. However, I've been living in DC for the past 3 years and am near certain I want to practice in either DC, Philly, or NYC. I am much more comfortable in a "Northeast corridor" environment, so I felt I would be a little out of place at Vandy.
If you finish top 25%-35% at either school you will have a plenty of options available to you, so if you are indifferent about where you want to practice, it's all about where you'd feel most comfortable. Outside of OCI, it will be easier to network in DC/Philly/NY from GW because of its location and number of grads. If you want mid-south/southeastern cities such as Memphis or Atlanta, then Vandy might be preferable.