The main asset of this flat is its location in the center of Madrid, in a really nice district with lots of bars and restaurants, and at walking distance from most of the main museums. Would recommend it for that.
However, I would not recommend it for 4 big guys: the bed in the living room is way too small for 2. And the flat is not very practical - you can tell nobody lives there.
Overall: a decent flat, a somewhat impersonal welcome, and a really nice district