Concur on Reston being waaaaay too far out. It’s great if you want to visit the Udvar-Hazy center (the Smithsonian air-and-space museum’s branch near Dulles Airport) but not for anything else.
Ritz-Carlton Pentagon City is well-located in that it’s right by a Metro stop. There are some better chain restaurants nearby but otherwise nothing too exciting. Dunno too much about most of the others, except the location of the hotel at l’Enfant Plaza is indeed convenient to the Metro but not near too much else you’d want to visit. I mean, it’s walkable to some Smithsonian museums but IIRC there aren’t any great restaurants there (mostly a shopping plaza that caters to the government lunchtime crowd).