We were a family of 4 (Grand parents, daughter and grand daughter) and we had plenty of space.
The appartment is well furnished but some glasses and cups were missing (no water glasses, only champagne glasses and only 2 mug cups) in the kitchen. Then we just bought 2 mug cups at a 100 yens shop and left them and it was OK.
The appartment is situated just near Nippori Station and it's really convenient to go to central Tokyo or to the Airports.
There are also plenty of restaurants and shops nearby.
Host were realy friendly and helpful.
We highly recommend this place and will surely book next time we come to Tokyo !