Really enjoyed staying at the B&B while at a conference in the Hilton (right around the corner). I enjoyed the unique details of this B&B over another boring conference center. The breakfast was really delicious and convenient and the rooms were well stocked with the amenities you'd expect at a hotel.
The street noise was substantial in my room facing the street on the second floor (not too much you can do about that in DC). You may want to ask about a room at the back or just bring ear plugs.