Overall, it is a good and convenient place to stay in. It is really near the train station and Shinjuku. It has everything you need to have a comfortable stay. Check in was also smooth.
However, it may not be as elderly friendly, the stairs inside the apartment is quite shaky and steep. And the bed frame is a danger, not sure if it is just us, but all of us kept hitting the bed sides of the bed frame and got bruises from it 😅 so do be careful if you are visiting.
Nonetheless, was still a great stay! Host was really helpful and responsive.