Perfect in every way, even down to the tiniest details. Location is exceptional - close to lots of great food (and beer!) but without any road noise. Less than 20 min walk to everything you want to see and revisit. I highly recommend Rafa's place - read on for more details
Gabi checked us in for our one-month stay and was super helpful throughout our stay (great baker, by the way!). She pointed out all the supplies and provided extra linens so we wouldn't have to do laundry. The laundry machine, though, and drying rack were extremely useful. And having two sets of keys was incredibly helpful.
We loved having the second bathroom when there were four of us staying (yes, short people have the advantage in the bedrooms). Beds are comfy, rooms are tight, but there's plenty of storage, and you figure out how to navigate around each other (especially when there's a full house). Desks are always helpful and there are loads of dishware, outlets and mirrors (those of you who travel a lot know how important these items are).
Occasionally we would hear a child in the hallway, or people outside the bottom bedroom window (there's a drying line there that is used by building members, I think), but it was never an issue. Access in and out is easy with no steps to climb. Neighborhood is very safe - in fact, we never felt any issues at any time in Madrid, even after dark.
Last great point - quiet refrigerator! We stayed with friends at a fancy place in Seville and the refer sounded like an animal being strangled every ten minutes. Plus, the freezer works great and is spacious.