We stayed at Residence Inn Pentagon City last week for 5 nights. They have a free shuttle that will pick you up from the airport and carry you back to airport. Very close to Pentagon City mall, about a block, which is where the metro is located. This made it very easy to get into the city and the mall itself has many restaurants for dinner after a long day sightseeing.
Two nights during our stay the hotel had free dinner. One night it was turkey wrap with cheese, lettuce and tomato. This was served with salad and chips. Also a free bar with beer and wine. The other night they had grilled chicken sandwiches with salad, chips, beer and wine. This was great to come back to after a long day in the city.
Rooms were very large with small kitchen. Our room overlooked the Pentagon. I would highly recommend this hotel for business or pleasure!