We stayed for 2 weeks and the location was great! It's close to the train station, main shops and a nearby must-visit street filled with restaurants. There's also a convenience store ~1 minute walk, and a laundromat ~5 minutes walk from the place. We also walked a couple of times from the Shinjuku centre back to the place and it was a really nice walk.
Kei was very helpful, and we really appreciated being able to drop our bags off in the morning before we checked in in the afternoon.
The area itself is quiet and we loved finding some parks nearby. I highly recommend searching for the small craft cola shop that has a vending machine you can get delicious cola from!
Staying in the room you may want earbuds to sleep as the walls are thin and we could hear our neighbours.