It was nice staying in Diogo's place. The apartment has 4 rooms. Mine was small but cozy. What isn't convenient is that it was a big room, separated with a gypsum drywall into 2 smaller rooms. The details, including the room door weren't constructed with the highest quality, so the door would make sounds during a wind, and the sound isolation wasn't the best. But no bigger problems.
The shower is kinda tricky too. Due to it being with passing, not accumulated water, it would go on and off but hardly controllable. For that reason, water would go from super-hot to super-cold in a matter of minutes, and only in the transition in-between, you could actually wash with it, without being burned or freezed.
The bed was comfortable and nice to sleep in.
The street is kinda noisy but bearable. But the location is great! Just behind the Gran Via and at the edge of vibrant Malasaña. Many restaurants, bars, supermarkets in the proximity.
Internet is super-fast. Great if you planned to do some work as well.
Kitchen and bathroom were clean and nice, and big enough.
For the reasons mentioned above, I would recommend Diogo's place, for shorter stays. Maybe other room in the apt would be better suited for a longer stay.