We stayed 3 nights at Marlen & Yannick s' place.
Communication before and during our stay was super easy, they even helped with carrying our luggage upstairs.
Everything is super clean and cozy, the room is bright and the bed is very comfortable.
Both of them are very lovely hosts, with a lot of tips where to find for example a good Thai restaurant or answering every of your questions.
I would definitely stay with them again next time traveling to Amsterdam.