Apartment is tiny and will NOT host 4 people.

Room: Tiny. Once the couch opens up, it takes the whole room. It was also pretty cold. Windows are leaky. Otherwise has necessities for a traveller like hair dryer, kettle, fridge. even coffee machine
Beds: Couch bed was comfortable enough. The bed on the 2nd level is another story. It is tiny. We were three people and one of us had to sleep diagonally on the upper level with head hitting the ceiling. Very uncomfortable. It is impossible to fit 4 people in this place unless two of you are midgets or children aged 10 or less.
Bathroom: Horrible. Super tiny, low ceiling, no sink. One of us couldn't even fit there standing up straight so he had to go to a nearby hotel to take a shower. There was a hole in the window (and we stayed in February) and it smelled of mold
Terrace: looked nice and spacious but it was too cold to use it.
Host: Ruud was nice, friendly, helpful, provided advice and even gave us museum passes.
Location: 30-40 min walk to the center, 15 min walk to Van Gogh museum, 3 min to tram stop.
Another thing to note: apartment is located on the upper level of a very old building. So you have to literally climb up very narrow stairs. It was also pretty cold in the apartment

Overall: if you are 1 or 2 average height and size people who don't really care for comfort and are looking for a place to sleep, this might work if the price is low. No romantic getaways, larger groups or anyone who likes comfort and decent bathrooms.