I stayed at Michael's place for about a month, and can highly recommend it!
Michael was an attentive and communicative host, who provided all the info I needed for my arrival in a timely fashion and regularly checked-in to see if there was anything I needed during the course of my stay.
The apartment is very spacious and impeccably clean. I found the mattress was very comfortable and there were extra blankets available if needed. Access to the washer-drier facilities was especially useful during my stay and these are very modern and quiet units.
All-in-all this is an excellent place to stay for a trip to DC!