To start with: Ramón was a star: we had a very delayed flight and he waited for us for more than an hour in the apartment and never even complained about the very late evening check-in time.
Unfortunately, we had a bit of a medical emergency and had to cut our trip short and leave two days earlier than expected: Ramón was very understanding, and offered to drop by and be there when we leave the apartment.
The apartment itself looks exactly like in the pictures. I think it's a bargain for a couple of two good friends but be aware it's all one room and open space so you should know the person you are sharing with very well.
The location is top notch, several supermarkets and places to get breakfast or coffee, great public transportation and you can easily travel all across Madrid from here.
I will definitely reach out and stay with Ramón again next time I am in town.