It is very interesting and special to live on the houseboat. We had a lovely few days in beautiful Amsterdam.
Overall, i'm with the positive reviews...
I think in addition you should know a few things about the studio apartment:
The boat contains the owner's apartment and several guest rooms - that are separated from each other by drywall.
Orientation on the boat is initially difficult - as none of the various entrance doors are marked.
The studio only includes the room with the bed and the bathroom. All other pictures of the ad show other parts of the boat.
The small seating area on deck can only be reached from the outside.
Subjectively, i think the 40 sqm is doubtful, in fact the studio looks much smaller.
There is no way to store the clothes - no wardrobe, no regal, no coat hanger. The few existing kitchen utensils are open on the very small minibar fridge. There is no kitchenette or cooking facilities in the room (so the term "studio" could be misleading). Airing is only possible via 1 porthole in the room and 1 in the bathroom, so it can get very warm in summer. The portholes cannot be covered, so they may be easily visible from the opposite pier.
The owner are very friendly and (sometimes) respond to inquiries.
The ad text suggests a recent renovation, but according to the owner, this was 5 years ago (status 08/23).
Overall, I feel the property is expensive in relation to what you get.
This rating reflects only my opinion.