Seiji is a superb host! It was our first time in Tokyo and we had lot of questions regarding our stay. Seiji very patiently and promptly answered all of them every time we bothered him with questions. He also emailed us a manual which had useful information about commuting between the apartment and tourist locations , operating the appliances at home, etc.
The location is spot on with the apartment being close to all amenities (groceries are just around the corner, Shinjuku Sanchome and all major attractions in Shinjuku including the fire museum, toy museum, Shinjuku Goyen are at an easy walking distance). The apartment was very comfortable with great facilities enough to make my two year old feel at home.