I stayed at this apartment for three whole months, so I will review with some details.
Host: caring and available in case of need.
Location: great. Between kabukicho and okubo, on a relatively quiet street (maybe some ambulances at night). Convenience stores next to the apartment, and big supermarket 5 minutes away. Next to Toei Oedo and Fukutoshin lines ( two minutes) which ate very convenient. Also 8 minutes walking to JR yamamote and 14 to JR chuo Sobu lines. Around 15 minutes walking to shinjuku station.
Apartment: clean and tidy, the host supplies you with towels and some other things like shampoo, body soap, etc. The sofa is not the most comfortable in the world but it does the trick. I know it can be for up to six people, but in my experience more than 3-4 with all the bags and everything it gets small.
Wifi: you get portable Wi-Fi included that you can carry around and connect two cellphones. The network is not the best again, it may not work on basement/metro, but it's okay.
Overall a nice stay in a very well communicated apartment. Thank you for everything!