Mas truly is the best host I've ever had. His communication is excellent, he always goes out of his way to help you (without even being asked!) and his house is to die for.
We stayed for four nights and loved that it was in a less touristy area of Tokyo. Before too long you feel like a local and are treated like one too. The area is 20 mins from everywhere in Tokyo and just a moments walk from the subway.
It's filled with great restaurants and wine bars with a cute little coffee shop (Mojo) just a few hundred meters away.
When I next return to Tokyo, I'll definitely stay here again.