Our 2-bedroom unit was spacious even for 6 of us during Christmas week. Our only (small) complaint was that the wireless Internet was not strong enough for mobile devices. Our computers were fine in picking up the signal, but we found that we had to use them (and the mobile devices) in the dining room for the best signal.
We tried to use the resort free shuttle to DC, but we found that the return times were not compatible with a tourist's schedule. We used the nearby NH1 public bus from/to the resort to the Branch Ave. Metro (green line). Service was good and on time. Parking @ $11 per day (billed to our room) was right across the street with in/out privileges.
We spent most of our time in DC and didn't do much in National Harbor although it is an upscale town with lots of dining opportunities. We found it easier to eat in the condo where cooking was easy in the full kitchen. The fitness room, pool, and hot tub were excellent for a hotel. Our grandson enjoyed the game room, especially the foosball. The staff was friendly and helpful. We used points to stay at the Wyndom and would happily return if we could get in again. It seems to be a popular destination for families.