It's a nice place to stay for couples. It's a nice residential area and only 13 minutes walk from the Union Station. We did take Lyft/Uber a couple of times from Downtown DC to get back to the apartment. The communication with Alex was great and he even asked if we wanted additional linen during our stay.
In terms of issues, I agree with previous reviews where they said that you can listen clearly everything that happens on the upper apartment. The other issue was that while taking a shower, the water temperature varies a lot, so you will have both warm and cold water during your shower. Since I prefer warmer showers, this wasn't so nice.
Besides that we had a great time during our stay, we liked the place, the couch was very comfortable, everything was very clean (except for the shower curtain), and Alex provided us everything, including towels, bed sheets, comforter, clothes iron with the iron board, and cleaning stuff.
I would recommend Alex's place to anyone going to DC.