Ariel's place is a great pick. It's perfectly located in the heart of Madrid, easy to get to from anywhere by foot and the metro is steps away. The area is fantastic. His place is super clean, comfortable and I would highly recommend it. If you are Coeliac there is also a gluten free bakery less than a block away. Heavenly gluten free palmeras! Ariel is very helpful and friendly. He was easy to contact, there to greet me and gave me a nice map of the area. I have absolutely no complaints. Great place!