This is one of the most unique and scenic places I've been to.
The check-in time was very flexible and they even picked us up by car at the nearest train station, just so we wouldn't be walking in the rain to reach the place. I mean, if that doesn't transpire care and good faith, I don't know what does.
We (3 people) stayed at the airbnb for 8 nights and it was a treat. The whole house in the river is beautiful and the sorrounding garden was very picturesque and quiet. The house is divided in 2 parts, one for the guests, and another for the family. Our part of the house was completely independent and had everything we'd need to stay there for long periods of time. We could cook some basic meals and have a proper bath, without any worries of bothering anyone.
When we arrived, the place was as clean as it could be, they even had amenities like snacks and beers for us there. They also provide clean towels, umbrellas, bikes, the whole thing. Having bikes is also really useful to get around and enjoy the city.
Highly recommend the place if you're visiting Amsterdam, not only for the beautiful and very calm river scenery, but also because the place is just a 10 to 15 minute bike ride from the main stations and the city itself.
Once again thank you very much for having us, we had a great time and we couldn't have asked for a better place :)