We had an enjoyable stay at Sun's apartment.
Location is perfect and walking distance to most attractions. The apartment does exactly what you'd expect and want for a brief city break in Amsterdam.
As already mentioned by most it is quite a steep set of stairs to navigate so do bear this in mind. Bed felt slightly sloped which wasn't too impactful for the duration of our stay but may have been an issue if we were to stay longer. Value wise it was on the more pricey side for what you get but nothing astronomically out of proportion (relative to Amsterdam).
All in all Sun's apartment did exactly what we needed and we would feel happy to recommend this place to others.