This is an awesome location for your stay in Tokyo. It is near Shin-Okubo station for quick access to the train, but an incredible walk down to Shinjuku along small roads lined with shops, restaurants, and bars, with each street full of trendy Japanese men and women of all ages.
The apartment itself was very clean, and a decent size for two people with two large suitcases and carry-on. It's tight, but this is Tokyo. Despite the streets being very busy during the day, you will have a nice quiet sleep as late-night people will be down in Shinjuku and away from the apartment.
Overall, highly recommend staying here for your trip. Cheers!