We had 4 people in Alex's houseboat for 2 nights and had a great time. It was a very unique experience! We were there in early May and the rooms were a little cold at night (7 deg. C outside) but we were fine once in bed. There is a wood stove that I am sure would warm things up significantly but it wasn't THAT cold that we would go to the trouble. During the day it was fine. Bed in the fore bedroom is more like a ship berth with little room above the bed (you have to crawl in). This was fine for us but might bother some people who are claustrophobic. The aft bedroom is "normal"
The boat is in a nice, quiet neighborhood and there are a couple of grocery stores and nice café very close by (Nassau café). Located close to the train station and downtown. Unless we had baggage we walked everywhere.
Since we were there for a short period we didn't fully unpack but I don't think there was any closet space available although I admit I only opened 2 sections of the closet to look so there may have been some.
There was one towel for each guest but they were small. Alex advised me that the toilet door had been broken and was replaced with a shower curtain. As a result there was little privacy from the other people on the boat. One again this was fine for us but might not be great for everybody. Hopefully he will get it fixed soon!
Although it may not have been PERFECT we really enjoyed our time there and would highly recommend it to anybody who has wanted to stay on a house boat or is looking for a unique "Amsterdam experience".