This isn't necessarily the place to come for ultimate luxury or the stereotypical tourist's part of the city, but if you want to experience real Madrid (or even Real Madrid - the apartment is not too far from the Bernabeu, after all!) then Fátima’s apartment may well hit the spot! It is small, there's no denying it - I stayed there on my own so had enough space, but two people, especially if you are quite big, might find it more of a challenge (the bathroom and shower in particular might be an issue for those of a larger build) - but its location is great, all amenities are present, and it makes a very good base for exploring the more interesting parts of the city (I definitely recommend Polar beer bar!). No steps to worry about for suitcases either - definitely a bonus.
Communication and check-in and out were absolutely brilliant - Fátima makes sure that everything is OK, and she was particularly accommodating with my awkward check-in time. If you've been on the road for a while the washing machine is very much appreciated, and there's a desk space if you need to do any work. The neighbours in the apartments around are quiet so you'll get a good night's sleep. I personally found the bed quite a bit softer than I'm used to; again this is a personal thing so if that's what you like then it's great, but it's worth bearing in mind just in case and it didn't impact on my sleep.
Gracias Fátima!