I stayed 5 nights in October and really enjoyed my stay. Everything about the house itself is comfortable, charming and very homely.
The house was exquisitely clean, the kitchen and bathroom are modern and very user-friendly, and the house has a very vivid sense of its architectural history as a small traditional Japanese home. Interestingly, Ryusei's house is like the Tardis: bigger on the inside that it appears from the outside!
The location is excellent - literally just around the corner from several Hibiya line station entrances. An easy walk to Ueno Park and station (convenient for transfer to the Shinkansen as well as many other lines). The area has everything needed for daily shopping, including a wonderful bakery a few steps away.
A little gem in the midst of vibrant and every-changing Tokyo.