Martin's place is as described, and as represented in the photos and in a top notch location. Albeit the bed and couch could have been more comfortable. The doorman (Portero) Tito was amazing and very hospitable, he took good care of us.
Make sure to note your arrival time carefully to avoid mishaps.
Everything worked out great and we were comfortable for 7 days. Coming from a 4 star hotel was a bit of a shock, the place could have been cleaner. But no worries.
Gracias