If you are travelling with kids, this place is perfect. My family and I stayed here during my last work trip to Tokyo and thoroughly enjoyed it. There was so many things for the kids to do in this place that if there was a rainy day we didn't need to work out how to entertain them. In fact they preferred staying in vs going out.
Compared to other listings in this area there is space to "live in" (rather than only for "sleeping in"). You can literally run around with the Minecraft swords or just chill / hang out in the "swinging UFO" whilst watching Netflix. There's a big kitchen and the location is close to Ozeki (supermarket) or MyBasket. There's an abundance of towels and a big washing machine so you can travel light.
For me and my work trip, travelling to Shinjuku and Shibuya was super easy - about 10-15 minutes by train and there were ample taxis on Chazawa Dori when I had to go further (eg Azabu or Haneda). We used to live in Shimokitazawa and this location is really good.
In terms of communication David was extremely friendly and quick to respond. He even ordered a brand new humidifier before we arrived because we travelled during winter and he felt it would be useful (it certainly was!).
Anyway, this place is highly recommended - we hope to come back again next time I have a work trip to Tokyo!