Kristiaan is an excellent host. The flat is really nice and well equipped. He was always super fast answering our message both before the trip and also during our stay. I could only recommend chosing him for your stay.
Kristiaan's place was quiet and clean. The building looks a little old on the outside but his apartment is simply but tastefully modernized inside. There is little street traffic so the neighborhood is pretty quiet other than kids playing. The garden patio was an unexpected plus. The location is very residential and suburban, with not a lot in the immediate neighborhood - just a grocery store and 2-3 restaurants. The proximity to Westerpark is very nice, and we did find some nice restaurants there as well. That said, the grocery store around the corner was very convenient! Although on the last day we discovered that it probably has another whole floor, which would explain why we couldn't find some things there. The walk from the train station was longer than we expected and we probably wouldn't do it that way again (with our luggage and toddler). We rented bikes while we were there (which Kristiaan had helped us to research ahead of time) and were able to lock them up in the front garden. Biking to city center only took 15 minutes or so. As Americans who don't speak Dutch we had some difficulties figuring out some of the appliances (like the oven and the clothes washer/dryer which are unlike any I've used before), but we were able to figure it all out with help from notes Kristiaan had sent beforehand. We never got to meet Kristiaan since he was away while we were there, but he was very helpful before our arrival. We picked up the key from his neighbor, who was also very friendly and helpful.