My family and I stayed on the 1st floor of Crescent Moon for two days. It's a very clean, simple space. There were great amenities such as a washer, wi-fi, microwave, toaster, stove top, refrigerator, house slippers (good for cold, winter days!), kitchen sink, and hair dryer. There is no clothes dryer, however there is a coin laundromat nearby, just a few minutes walk.
The Marunouchi subway line is a close enough walk away, and there is a Maruetsu grocery store nearby. The neighborhood is quiet, which makes for good naps and bedtime for little ones. We didn't find too many good places to eat nearby, however we spent most of our time in Shinjuku which offered a good variety.
I would recommend this place, and would stay there again. The staff helping Kyunga were quick with their responses.