Alberto is the best! He welcomed me with wine and snacks and a very detailed map and overview of the city's attractions. I had inquired if he might have a guitar (I'm studying and didn't want to lose my callouses!), and even though he doesn't play or have one, on my second day there he knocked on the door and had found one for me to use!
The apartment is perfectly located near Plaza de la Puerta del Sol, near outstanding dining and nightlife, but is quiet as well. It's small, but works well. It's a fourth floor walk up with no lift, but that allows you burn off some of the jamon and cerveza and queso that you will certainly be imbibing!
Alberto works nearby and was very responsive to questions and needs.
Really, an excellent experience overall, highly recommended.