The location is extremely great, a very short walk away from Otsuka station in the JR Yamanote line, which is the main train line to travel to hotspots around Tokyo. The apartment was very clean and cozy, the bed was extremely comfortable. I can happily recommend this especially for solo-travelers like myself, though you can definitely stay comfortably with 2 people.
Things to keep in mind: 1) in the room I stayed there was no Pocket Wi-Fi, which was advertised in the room description and 2) during check-in, the key was not where it was instructed to be and the correct location was only told after I myself first messaged the host to inform them the key wasn't there.