Location
It's excellent. 2 stops away from Shinjuku station and I love the away from the super insanely crazy human traffic in Shinjuku.
It's actually quite close to the Government Metropolitan Building and Hilton Hotel.

How to get there
Alight Nishi-Shinjuku Gochome Station on the Oedo Metro Line. Exit A1 from the station, Turn Left. Make a left turn to the small lane before 松屋.

Overall
The place is very clean. The room can accommodate up to 4, but I would think max 3 will be comfortable in there. Kazumi also provided some Tokyo Handy Guide and maps in the room. The wifi is also very helpful to us. Kazumi is also extremely prompt in replying messages. I will definitely recommend any of my friends to stay there.