We enjoyed our stay at Riki Flat. The apartment was clean and we found the location quiet at night. The stairs are quite narrow and the room was on the smaller side, but most places are small in Tokyo!
With train stations close by, the location was also good to access Tokyo and Shinjuku. We could also walk from Shinjuku to Riki Flat in 30mins or so.
Overall we had a good time and would recommend this place to stay when visiting Tokyo.