We didn't get to meet Christina, but we had no problems checking-in or checking-out (a friend of hers was waiting for us at the arranged time) The room was as described, clean and cozy. The only thing missing was a closet in the room. It's a bit small for one, but a custom one I think can be built...
The neighborhood is perfect, Williamsburg really is an up-and-coming place and the apartment is in the center of it, full of people night and day, but you never feel the noise when you are inside. You can eat your breakfast, lunch or dinner in a different place each time and you'll still not cover all the interesting places. The subway is literally 5 minutes away, and one stop to Manhattan.
If you have a big bag be sure to be fit, because the apartment is at the top (3rd floor) and there is no elevator.
Although Christina has a roommate we only saw him a couple of times and we felt like we had the apartment all for ourselves.
Definitely I would stay there again if I am coming to New York in the future.