I was staying with Christa and Zach for more than a month (for my studying rotation). It was really a great experience. Despite being far from my family for such a long period of time, I felt comletly at home thanks to the guys' hospitality. It was especially a big pleasure to enter the house after a hard and exausting working day, to have a good conversation with Zach or Christa, to have some fun with two buddies (obviously, I'm speaking about the dogs:).
The house is very cozy, clean and well-decorated. I could find everything I needed for my entire month stay. The neighbourhood is completely safe - checked it at every time of the day:) A subway train will give you a pleasant ride to any attraction you need in Manhattan and not only there.
During my long stay there were a lot of guests who where coming for shorter periods of time and staying in the other guest-room, and everyone was really satisfied by everything.
If you consider coming to New York for any purpose - vacation, studying or business - this is definitely the best place to stay!