Two things make this place super great:

1) location. Close to a park, close to subway stations, walking distance to union square and away from the tourists! Just the block the apartment is at would probably be worth the visit. There is the best burger in NYC - and I know this is quite a statement! - which happens to be vegan, at the superiority burger. There is a lovely breakfast place called Zucher Bakery. A great wine shop. An amazing hair dresser. A lovely gifts shop for kids. A great trendy restaurant... Seriously. I don't think I could be in a better location. And yet it's quiet. My 5 month old slept super well, close to the windows even o Friday and Saturday. So, seriously amazing location.
2) host. David is considerate, caring, great to communicate with and super reliable (if you are looking for a place in NYC you will notice the amount of "the host cancelled the reservation x days before arrival", so being reliable is so important in the city!). David is the kind of host who makes airbnb great!