Uncomfortable. Although this apartment is located in an amazing neighbourhood, it is pretty different from the photos: it is around 5 m2 (everything combined), it does not have any sun light (there's only a small obfuscated window at the ground floor), and was overall very humid. For our specific stay, the blankets did not appear to be clean: they had stains, smelled weirdly and were a bit moisty - when we talked to the hosts about it, they dismissed it. Also the towels weren't great. Even the internet connection didn't work properly at the room.
On the positive side, they left some nice coffee and enough cooking utensils; the building's balcony (on the 4th floor - with an elevator so slow it was scary to use) had a great ambience both during the day and during the night; the street outside of the house is full of people sitting outside making for an incredible atmosphere.
It felt overall to be a bad quality/prize relation.