My fiancee and I had a fantastic week in Jason and Ondine's place! We dealt mostly with Ondine and she was very pleasant and helpful but also gave us plenty of space to just come and go on our own, which was exactly what we wanted.
The apartment was perfect for us - up a couple flights of stairs, but that was no problem for us and Ondine even insisted on helping us with our luggage. The bedroom was cozy and *very* conducive to good sleep. Nice sitting room for us to make our "base camp" and a good, clean bathroom. The shower is a little awkward because of its location under the peak of the roof and because my fiancee and I are both pretty tall, but we made it work just fine. The BEST, most wonderful thing during our stay was the AIR CONDITIONING. It was a heat wave pretty much the whole time we were out there and without AC we would've been miserable. The windowbox air conditioners in the bedroom and the sitting room were fantastic and cooled the place down within minutes of our return every day. Seriously - they were a godsend.
The only hesitation I'd have staying here in the future would be that most of our time was spent in Manhattan and Staten Island wasn't the most convenient location for that. Going in and back once a day was fine - the ferry is fun and reliable and free - but if we wanted to go to the city for the day and then come back and change before going back in at night, it ate up a lot of time. BUT that's why the rates here are so much more reasonable than staying in Manhattan, and that was a priority for us, so this was the right way to go.
In summary, this was pretty much a perfect situation for us - a whole floor of a nice house to ourselves, really pleasant and helpful hosts, at a great rate. If that's what you're looking for, I highly recommend booking here! I bet we'll be back some day. :)