Michael was out of the country during my stay but immediately replied to every message I sent (mostly regarding my arrival/departure logistics), which impressed me. The location is fantastic! It's a straight shot of a couple of blocks to the Dupont Circle metro. On a nice day, which I was lucky to have, it's a pleasant walk to the major attractions on the mall. Trader Joe's and Whole Foods are close by, as are numerous restaurants and some pretty, historical churches, including one that was attended by Theodore Roosevelt while he was president. On Sunday, there was a very nice farmers market by the metro station (http://freshfarm.org/dupont-circle.html).
The apartment was impeccably clean and very airy. I noticed a laundry room off the hallway but didn't investigate, as I was only in town for a long weekend. There always seemed to be residents walking dogs and riding bikes in the (upscale) neighborhood when I was coming and going, and it felt very safe during both day and night. The other residents of the building were quiet. Had I not encountered a few folks in the halls, I would have thought myself to be the only one in the building.
The only consideration might be for someone who has difficulty climbing stairs. There is an elevator to the third floor apartment, but the loft with the bed is up a flight of stairs (but that's also what makes it so cool!). Other than that, I would highly recommend both the host and the accommodation to fellow travelers.