I'm writing this as an American male who traveled with 2 other adult American males. 2 of us are 6+ ft tall. None of us wanted to share a bed. So, I booked this place as it had 2 bed's and a sofa bed. The sofa bed has a very stiff bar that sat right at my back when lying down. It made the bed unuseable as designed. I resorted to taking provided mat, which was very thin, and placing it directly on the hard floor.
The bedding doesn't appear to be washed on each visit. We found hairs in the bed and the bedding for the sofa bed had old dust, as though it is washed only every few months. In addition, the cover for the sleeping mat for the sofa bed seems to be very difficult to wash, which makes me think it is rarely washed. This problem could be solved by a top sheet, but none is provided.
Trash cans are rare in Japan, at least compared to the US. There are many warnings about disposing trash properly. However, the provided trash cans are tiny for 3 people, especially in a country where you buy several bottled drinks daily. That said, the provided liner is large, so we pulled the liner out of the trash can and had this big trash bag sitting in the kitchen.
Another inconvenience is that there is only one set of keys. This was especially inconvenient for us as one of our friends got sick and needed to stay at the Airbnb for 2 days. The 2 of us who were healthy had to leave behind the key and hope our sick friend would be awake or at the Airbnb when we arrived back from exploring the city.
One final minor complaint: there is a small step leading to the restroom that all 3 of us stubbed our toes on multiple times. It is a minor complaint, but I guarantee it will piss you off.
The primary positive for this place is the location. As advertised, it is a short walk to a subway station which is only 2 stops away from the Shinjuku station. Shinjuku is the busiest train station in the world and you can get to just about anywhere in Tokyo (maybe even Japan) from this station. I suggest learning how to get to Shinjuku station from the nearby station (Nishi-Shinjuku Gochome). If you do, you will likely be able to figure out how to get back to the Airbnb even if you lose your phone or GPS. By the way, the host sometimes refers to 5-chome. "Go" is "5" in Japanese.
Overall this place would be fine for 2 adults who want 2 separate beds. In fact, I'm planning another trip to Tokyo with just one other friend, and I'd consider staying here. However, I think it may be cramp for more than 2 using 2 beds and I would not suggest this place at all if you want a third bed. I'm writing this review based on my personal experience with 3 adults using 3 beds, so I must only give it 3 stars with the third star being for the great location. If I didn't have to use the third bed, I believe I would give this place 4 stars.