Paz Y Alvaro's place is fantastic and in a great location. We were three people staying there from May 24th-27th. The apartment had pretty much everything one could think of. The communication was prompt and check in was smooth. I really cannot think of anything that we missed. If there was one thing that could be added that would be a kettle for us tea drinkers :).
Just a note for people who might have a car (not needed in Madrid at all if you are only doing the city and not driving out of it) - we booked ahead through Parclick.com. Parking on the street is next to impossible and mainly for residents. We had a car since we had trips planned out of the city. We parked in the garage mentioned in the apartment website and since we booked ahead we got decent rates. Just make sure about the opening and closing times of the garage (especially weekends) since its different from what's mentioned in the website.
Do not hesitate to book the apartment! We will definitely be back!
Thanks Paz and Alvaro!