The location of the apartment is amazing. A 5 minute walk from Daitabashi station which in itself is only 10 minutes away from Shinjuku on the train. You can even walk to Shinjuku in about 45 minutes by following the main road (I recommend you try walking at least once and to get a feel for the area).
The surroundings area around the apartment is quiet but a 2 minute walk towards the station and you can be back in the hustle and bustle of Tokyo. Daitabashi has everything you could need in your immediate vicinity.
My only concern is that the WiFi is not perfect, you'll struggle to google anything from the apartment and will just about be able to message people on Facebook.
Aside from that, I very much recommend this apartment as the place to stay in Tokyo and if I were to return this place would be top of my list for accommodation.