The home is very nice, and generally as described. It's definitely a bit of a treasure hunt to find the key to get in, and I can understand how some guests especially arriving late at night might find the experience a bit unsettling. I don't think anything was at all unsafe, but I expect that's what some of these reviews are about.
Mat gave us good directions and was responsive when I called him with a question.
The main thing I'd caution is that the basement, while technically a private room, doesn't have a door that locks but rather a staircase. I'm not sure if this is the norm with this home, but the other room upstairs was being rented by other people (who we never saw but saw signs of -- and didn't get to pick based on reviews like we do with hosts), we would have liked to lock the door when we left our laptops and passports in it.
There's definitely space to sleep 4 people in the basement, so it's a great deal. The food nearby was great and the subway was nearby. Everything was clean and nice.