We just spent six nights at Maarten's amazing apartment! We loved everything about it - it is walking distance to Dam Square and the city centre but far enough away that you feel you are in a local neighbourhood and away from all the craziness. There are lots of restaurants and cafes nearby.
The apartment itself is awesome. One huge benefit is that it is just a couple of steps down from the street, rather than up flights of skinny steps as is often the case in Amsterdam. It's very stylish and exactly as it appears in the photos.
Maarten was super responsive and checked in with us a couple of times to make sure we had everything we needed - they had also stocked the fridge and cupboards with some goodies for our stay!
I wouldn't hesitate to recommend this apartment!