A few things.
1. This place is indeed sparkly clean.
2. Very convenient to the subway station (Higashi-Shinjuku Station A1 exit is right across the street) but please take note that there's some decent walk underground if you are taking the Fukutoshin(F) line. Oedo(E) line is a very short walk.
3. There's a Lawson convenience store around the corner, which is super helpful.
4. I suspect the passcodes are never/seldom changed. Therefore, always physically lock the door using the latch. Do not leave valuables when you are not there - we didn't encounter a problem but were very cautious.
5. The wifi was not working. When I asked the host I was advised to connect to the wifi on another floor since there's a wifi on each of the three floors. Unfortunately two out of the three are not working, and the last one worked but quite slowly. I ended up using my cell phone hot spot.
6. The washer can also be used as a dryer. It is air-dry though, meaning it takes quite some time and not working well. Be ready to take another set of clothing to allow time for hanging dry.
It was an overall pleasant stay.