The apartment was more than comfortable. Down a lovely residential street about 20 minute walk from the main area of Amsterdam. Very easy to navigate to and from as it's very close to a couple of popular attractions.
The staircase was VERY steep, but this is traditional of the buildings. Just bare this in mind as it's up two flights!
We met the neighbour opposite and the couple living below, and their cat - both were very lovely and very helpful.
It was quite noisy throughout our stay, but this was because there was building work in the apartment opposite - if you're a light sleeper I would suggest earplugs (even without the building work) but that goes for any trip you'd go on.
There was a really great pub/bar one street over, and a couple of cool bars not too far walking.
All in all I had a lovely stay despite not meeting my host, and would most definitely return to Maartens apartment.