It is a nicely decorated flat. Cozy, stylish, new and clean. Very close to what the photos show. Its space is good for two persons and is much bigger than the usual hotel room in Tokyo.
It's located at Kagurazaka, which is a place with lots of good restaurants! It however needs change train twice when going to and from airport. I suggest to take a cab to or from Tokyo station especially if you carry large luggages.
Mas is kind and he provided well organised information for transportation, restaurant recommendations etc.