I had a wonderful stay at Paula's apartment. I stayed for two weeks and it was very comfortable and clean. Everything works great (bathroom, kitchen, washer, wifi, etc.). Paula was very good about responding immediately to any questions I had and was very helpful. The young woman who cleans (Cherrie) was often at the building and was super helpful with any questions I had as well.
Since I was there for a while, Paula even offered to have the apartment cleaned once during my stay, which was very nice! The location can't be beat--walking distance from the Prado and Reina Sofia museums, and lots of bars and cafés within walking distance. Others have mentioned the noise, which is true. I don't think it's mostly from the bar downstairs (which wasn't always open) but rather from people walking by and cars and trucks going by. You can hear them clearly (sometimes loudly) from the apartment. It was not really an issue for me and I was able to get to sleep just fine. Overall, I highly recommend it, and Paula is a fantastic host.