The room is exactly as described in the pictures. The location is at the heart of Malasaña and the facilities were always clean. The check-in & check-out is extremely easy as everything is prepared automatically. I didn't even meet the owner. So, this isn't a place to interact with locals. Instead, a great option to explore Madrid by yourself.
Downsides: 1) The rooms can't be locked, even though you can lock the wardrobe with a padlock. However, I have to say that I didn't feel unsafe regarding this manner. 2) The floor is made of wood and is very noisy. Other guests were very respectful so this wasn't an issue. I could hear them coming in or out, but that's all. However, if there is more movement in the house it may bother you.
Long story short: I would go for it again :)