We had a lovely time staying in Mario's apartment. We never got to meet Mario himself but his girlfriend was very helpful and easy to pick up the keys from. Gramercy park is a good, safe area to stay and although I wouldn't say it is thriving with bars at night, it is perfectly central to pretty much everything on Manhattan. The apartment was clean and comfortable and Mario communicated quickly in response to any questions we had. All in all, a very positive first experience of New York and we wouldn't hesitate in staying again. Thank you :)