The room in Frank's apartment was a great value and the location was great as well. We were close to the Vondelpark, the Rijksmuseum, and a hub of activity around the Leidseplein area (for the first evening, we hopped on a canal cruise from there) - I didn't feel the need to even use mass transit very much during our stay in Amsterdam, as so much of the city was walkable from where we were. It was easy to get there from Amsterdam Centraal, and easy to get to the airport from on the way out.
The door from the street was a little tricky to find initially, but everything was easy after that. The stairs were no joke, but I soon found that steep staircases are pretty normal in Amsterdam! Inside, we had what we needed - a nice bed, a pretty spacious room, and a bathroom/shower. It got a little toasty when we were there, but I understand it was unusually warm while we were there (so not too bad on the whole!).
My girlfriend and I accidentally broke something in the apartment, and Frank was understanding about coming to a resolution on that, so I appreciated his gracious attitude as well.
All in all, I felt I'd made a great decision to stay at Frank's place!