I stayed in this apartment for 2 nights over Thanksgiving. It's a nice apartment, spacious and comfortable. It's quite close to the sites, I had a car which was great for parking but it would only take around 30 mins to walk to the Capitol building.
The neighbour upstairs is really lovely, and the neighbourhood is quiet and seemed safe.
There's a good shower, cable TV with loads of channels & everything you need in the kitchen.
I didn't meet my host as she was away for thanksgiving but she was great at keeping in touch and providing information, and the door has keyless entry so it was easy.
Overall I would recommend this apartment for a solo traveller or a couple looking to stay in Washington DC.