Walking distance to Shinjuku station, located in a quite area In the heart of the city. The staff were very helpful and polite. The apartment itself was very clean and carefully maintained. Overall it was a very pleasant stay for us and we highly recommend this place if travelling with more than 4-5 people.
One suggestion is that due to the reception is not at the same place as the apartment itself, it would be better if the host can send some sort of pdf guide to guest so it will be much easier to checking in.