Masami was very responsive and helpful. I really liked the location although watch out if you get a Metro pass, the Hatagaya station is on the Kieo New Line so not on all the subway maps and separate tickets from Metro. Only two stops to Shinjuku though, so location was very good and central.
The neighborhood has some great restaurants and convenient shops nearby.
The flat was very clean and quiet. Good instructions for appliances except the heat we had to figure out, but easy enough.
Comfortable beds that can sleep 4 easily. The fold out couches were a little short for the guys but the beds were big enough to double up so it worked out great. Would definitely stay here again and highly recommend Masami's place.