Got in early, so met John at his office in Manhattan to get the keys. Other than that, didn't have much interaction with the hosts (given it was over the Christmas holiday).
Firstly - the location is wonderful. Right by the Greenpoint Ave. G station. Sure, the G Train isn't the most sexy of lines, but it will take you to all the happening neighborhoods of Brooklyn, and it's a couple stops in either direction to transfer to a Manhattan-bound train. Also, the walk to Williamsburg was pretty easy...about 15 minutes or so, and you're at the Bedford Ave. L station. One night it was rainy and cold, so we cabbed it back from the Lower East Side, and the fare was about $18. Not terrible.
I also have to mention the amazing food options nearby. Karczma, a Polish restaurant basically across the street, is not to be missed. And for 5 days straight I had to hit Manhattan Ave. for a bagel (2 great bagel shops within a 5 minute walk of the apartment).
As for the apartment itself? The bed was comfy and the room is surprisingly quiet, as it faces an interior ventilation shaft. Thus, no street noise. It's also nice to have your own bathroom, which is pretty basic but has everything you need. The apartment was a little dusty and could use some elbow grease, but it wasn't filthy. The interior has been rehabbed recently, so it's got some stylish modern touches. For NYC at this price, it's definitely a good value.