Koen was an amazing host. The apartment looks even better than in the pictures. It was clean, very comfortable and it's located in a very nice neighborhood. It has a very nice rooftop where we liked to eat our breakfast and dinner. Koen helped us a lot, he responds very quickly and gave us lots of useful information on Amsterdam. Also, he explained everything we needed to know for our stay in his apartment.
It is not in the center but Amsterdam is a very nice city and we liked to walk to the center every morning, it took about 25mn. Also, if you rent a bike, which we did, it's very easy to go the center and not very long.
I can only recommend Koen's apartment and I'll definitely rent it again if I come back to Amsterdam !
So far, it's my best experience with Airbnb. Thank you Koen for being a great, thoughtful host!