We had an excellent stay at Carlos' place. The appartment is perfectly located in a young and relaxed neighbourhood, and is a very good strating point to explore Madrid, which we did extensively.
The appartment is realy nicely furnished and equipped with erverything you need. For us traveling in two it was absolutely spacious and comfortable, however it can easily accomodate anther two people for a weekend or so. We most enjoyed the comfortable bed(s), the good shower, the fact that there is a lift (the place is on the third floor and it's really nice not to have to carry the luggage up there ;) ), the heating (important in January in Madrid) and of course the beatiful and stylish decoratin of the place!
Carlos and Amalia where there to welcome us and provided us with some beakfast for the next day as well as many valuable tipps about Madrid and life in spain, genereally.
A stay with Carlos and Amalia is highly recommended!