The host and the flat are both really great. The flat is spacious, very comfortable and in a great location. It is located right next to Atlantic Terminal station (it's a 30s walk to the entrance of the subway station). The station has a Target, Uniqlo, Guitar Center, and if you're willing to walk an extra 2 minutes you'll find a Whole Foods and an Apple Store. In spite of that the street the flat is on is very quiet which is quite a feat. From the flat's door you're in Manhattan (Central Street) in 10mn.
Kay did an amazing job as a host. She was very flexible with the check-in and check-out times and didn't mind spending close to an hour showing me the flat, telling me about New York and giving me suggestions for spots to visit.
Thanks again Kay!