Positives: heating system working extremely well for a Spanish apartment.
It's also close to subway, walkable distance to nearly all key monuments. Many restaurants and shops nearby.
Negatives: extremely loud neighbours during night hours (we're talking family reunions, music and arguments at 4 am!). The walls are paper thin and the apartment is ground level - you'll hear every commotion outside (drunkards, public services, cars honking, people coming and leaving the building).
As for amenities, it feels like everything was discarded from some else's house (broken knife, cd player without cds, candle holders without candles, old TV without HDMI socket, guide to Australia etc). It was our first AirBnB where we questioned if anyone has ever actually lived there (bed with no place to put your phone or water, unless you count the floor, sink in the furthest corner of the desk etc.)
And lastly: the host had automatic messages in English but NEVER answered any of our questions personally.