Our family of 4 was able to fit comfortably in the house. The central location near to Shinjuku station was great, as well as the convenience of having a 7-11 around the corner. We enjoyed the little touches of home, like the reclining chair, the projector in the living room, and a coffee maker!
We found the bathroom a little small, though that might be standard for Tokyo houses. Also be prepared to climb up the stairs to the 4th floor.