Honestly, one of the most pleasant airbnb experiences I've had far. (Reasons stated in form of list for the purpose of keeping the review short)
1. The apartment is situated in the neighbourhood of Chueca, on a street bustling with life (not in a negative way): supermarkets, tapas bars, restaurants, shops, you name it. Also, you're right next to the Gran Vía, which is one of the most central streets in the city.
2. It offers an access to various means of transport (if you're not a fan of walking): metro of Chuca and Gran Vía only a few min. away, as well as several bus stops all around.
3. Moving on to the room, mine was small (there are two other bigger rooms in the apt.), but cozy. It might have lacked a window, but, personally, I didn't mind. The bed was comfortable and I had plenty of room to store my things. Also, it has no air-conditioning, but don't hesitate asking if you can borrow an available fan/heater.
4. Finally, the hosts. I have no words to describe how wonderful Isdel and Olga are. From the first day, they welcomed me and my pet with a warm smile. Always there to offer their help, or, if you want to practice your spanish, a friendly chat. It was a pleasure meeting them both and I'll always remember the little tune they sang whenever they saw my little furry friend poke her nose into the kitchen.