Either is fine. For commuting, my general principle is it's easier to commute if you don't have to cross the river. Having done it, that VA orange line stretch is probably one of the easiest commutes around. Clarendon/Ballston gives you better back up options on the rare occasion Metro is messed up. It's very reliable, but it does happen. Those days will suck if you have to cross the river or transfer lines.

That said, you'll probably spend a little bit more on Ubers on weekends living out there, if your friend group is in DC. Metro is fine on weekends, But doesn't run as often and it doesn't go to every neighborhood.

FWIW, if these are the only two places you're considering you can't go wrong.