We (2 people) were guests in Davids Houseboat for our weekend-trip to Amsterdam.
Everything was great: From my first contact with David via AirBnB (very nice and fast in answering my messages), to our first meeting, where David even offered to pick us up from the Tram station, because it was late at night and so we could better find the boat.
To our room: yes it is small, but big enough for two people! The bed was very comforting, and there was no problem with the heat or hot water, so we could feel very well in this cold november nights ;) There was even a small water heater and a little tea/coffee station!
The toilet is on the floor, but exclusivly for us. It was nearly kind of a small "adventure" to go to the toilet, because while seating you have a nice view over the water ;)
Everything was clean and all in all nothing was missing.
Perfect place for short city-trips! Would recommend it 5/5, hope one day I can be his guest again :)