I have stayed at five Airbnb units in Spain and the US and never provided a negative review. This unit, however, is terrible. Perhaps for $50-$60 a night, it would be a budget option for someone willing to deal with the problems, but I was charged $145 a night. It smelled of cigarettes, not because anyone smokes inside the unit, but because of so much past smoking on the balcony and the cafes one floor below-- the AC condensers sit right there and can't filter out that much smoke.
Terra-cotta planters on the balcony were filled with old cigarette butts, there must have been hundreds of them. Miguel came and cleaned them out when we pointed out the problem, but this should have been addressed before we arrived.
The unit was very dirty. Large dust balls on the floor next to the master bed and throughout the unit. The entire building seems to be for sale and not being kept up. We had to contact Miguel because the switch to turn on the stairwell lights did not work -- and it is entirely black at night without that light. Miguel waited until his work day was finished to respond and then set a time for an electrician to come the next day, but we had to be present to meet the electrician, taking out time from our vacation to attend to the owner's responsibilities. The electrician was very nice and did fix the light switch, but this should not have been our responsibility.
The noise and cigarette smoke from Chueca Square is also extreme.
The small back bedroom has a window onto an interior light shaft, not onto an alley or next door building and has no AC. Very stuffy and you can't really open that window for any purpose. In the hot summer months, the room is hard to use.
There are many other options for rentals in Madrid at this price, I would choose one of them. We were very happy with the next Airbnb in Madrid which we moved to.