Mitsuko-san and her husband are very nice and helpful people. Mitsuko picked us up at Hatagaya subway station and guided us to the apartment. Whenever we needed something, she always helped us. The neighbourhood at Hatagaya is quite peaceful and calm, with mostly local and friendly people knowing each other. It seemed almost like living in a little village within Tokyo. There is a huge and a very nice park Yoyogi in the walking distance and you can walk to famous districts Shibuya and Shinjuku, too, or they're both reachable easily by subway line. There are lots of restaurants and grocery shops everywhere.
The apartment is very tiny, but that's what you should know when booking it. It was
clean and tidy, both bedroom and bathroom. It's totally okay for a couple, as the Tokyo visitors are surely not coming to the city to stay at home, but for heavily jet lagging European family with a small kid, it was rather challenging in the beginning. The walls in this apartment building seem like made of paper, everything is audible and quite loud. So if you or your kid has sensitive ears or sleeping, you should probably consider staying there.
Thank you, Mitsuko-san for your hospitality!