David is a good host, he is a reliable and flexible. If you look for a stay in Amsterdam which is affordable and in the city center, David's boat might be the right choice for you. It is mainly suited for couples. Old people should not book this accomodation because the stairs to enter the room and the way to reach it are a bit adventurous. The shower and the sink are in the same room as the bedroom. The toilet is in another room. The bed is not very comfortable but okay if you just stay for a few days. The area is calm even if it is directy in the centre.
All in all I would recommend David's boat if you look for a trip when visiting the city and you need an affordable place to sleep.