If price is not an object, although I've never been in these properties, by area, the capital is the furthest out of the way with not much close by. Vermont Ave. is second, bit closer to the sights but quiet at night.
Dupont is in a very good spot, easy Metro to sights, easy bus/walk to Georgetown, tons of places to eat in the area, easy run to Adams Morgan, 24 hour CVS - I prefer to travel to sights and have an easy time around my lodging. Your travel habits may vary......