We are 5 people who stayed at Alfonso's place for 5 nights. He was a good communicator, always responded quickly to my emails. We arrived early in the morning and he let us drop our bags off while they were still cleaning the apartment.
The apartment worked well for our group. While 3 of the 4 bedrooms are very small, the open plan living and dining/kitchen area is a good size. Some people could sit at the dining room table, others in the living room and we all felt together but not squished.
Neighborhood is good too. Within a 45 minute walk of all major Madrid attractions and close to two metro stops. Safe neighborhood with plenty of places to eat close-by.
Would definitely stay there again.