Stay here!! I spent 3 months living with roommates in Gisela’s apartment and it was an absolutely wonderful experience. The location of the apartment could not be better— you are within a mile walk of anything you would want to see and if you need the metro you are right next to two central metro stops. The apartment fit 4 of us pretty comfortably, though I would guess 4 is the upper limit for a long term stay. The best part of this apartment is the terrace which is huge and has a wonderful view. Gisela is also a great host, and she is very responsive to any inquiries you may have. She also has lots of great recs for things to do and places to eat around Madrid. Overall an amazing find, definitely stay here!