Nice little apartment in a good location. Great for exploring Tokyo as there are train stations (subway and JR-lines) in walking distance. Even the monorail station to Odaiba (over Rainbow Bridge) is not too far away.
The apartement is a bit on the small side. I'd say it's perfect for four people. If staying as a group of five or six people, it'll be a little bit crowded. After all I can recommend it if you are looking for a cheap stay for sightseeing in Tokyo.