Namio's place is excellent. It's a short, enjoyable walk from Ueno Park, and a stone's throw away from Nezu Station. As the house is situated in a residential area, it's really quiet at night, but there also a lot of quaint bars and cafes. There is also a nearby grocery and drugstore from which to get supplies. The unit itself was well furnished and quite spacious by Tokyo standards.
Namio was also very helpful in providing information about the area and the unit (Namio's guidebook was comprehensive). He also helped us in looking for a nearby place to rent bikes for a day of museum hopping. All in all, great accommodations and great host.