We were three girlfriends visiting Madrid for the first time for whole of 9 days, and staying in Maria's apartment was just perfect for that. There are enough rooms so that we each could have our own, and the location couldn't have been better. Everywhere we went, Maria's apartment was just in the middle, and yet it was still a quiet street.
Only one thing others might need to know: Maria has a small dog, which lives in the apartment, (but naturally isn't there when the apartment is rented), and so the apartment bears trace of this with some dog hairs around. It wasn't a problem for us, but for others it might be, with allergies etc.