At first: the appartment is perfect for a stay in the city. It is very well located, in the middle of the city so that you can reach everything by foot. If you don't want to walk, you can also rent a bike from the host. This is a very nice way to discover Amsterdam.
The appartmemt is very tiny, for 3 people it is okay, but I think it is to small for 4 people.
A highlight is the balkony, which is very nice to sit on in the summer. You sit above the roofs of amsterdam and it is really quiet.
You must know that the stairwell is very closly and steep, but for young people it is okay and we got used to it in the end.
Also good to know is that the bathroom is very tiny and that it is only a shower and a toilett, but no sink to wash your hand. You can do that in the apartment. For tall people the bathroom may be a little problem.
Diogo was our host: he was very nice and always communicated very fast and uncomplicated. He gave us a few good tips for our stay.
To conclued this apartment is nice for a city-trip. It is not luxurious, but we liked to stay there, because the location is perfect and the hosts a very nice & caring!!