We really enjoyed staying at Casilda's apartment.
The air conditioning was great (it is built-in so you have the same temperature in leaving room, bedroom and bathroom).
The wi-fi was fast - we didn't have any problems with it.
The location is perfect - 5-10 minutes to the metro station, 3-5 minutes to the beach, lots of cafes and groceries nearby.
The apartment itself has all the amenities you would usually need.
In the evenings it can be a bit noisy from the street but the windows are sound-proof and there are also blinds that you can roll down so that the street lights don't bother you.