My stay in the apartment of Pedro and Odette was OK but could have been much better. It's not the worst I have seen and not completely bad, but if you like quiet places and have high standards of cleanliness, I don't suggest it.
Positive aspects:
From the place you can reach Atocha and Sol on foot in ca. 15 min. The flat is at the ground floor and has an inner yard which blocks the sunlight and therefore protects from the Spanish heat. The bed is comfortable. There is a kitchen with fridge, oven, washing machine. The bathroom has the essentials. See below about cleanliness.
Negative aspects:
The flat is in Lavapies, a popular neighbourood; if you are used to a north-European feeling of safety, I don't suggest it and I will in fact avoid it the next time. Communication was fine before my trip, but I was not informed that Pedro and Odette were going to be on holidays during my stay, or that I had to wait at the entrance for a friend of theirs. It would have been nice to know in advance. Their friend was very nice and available to help if I needed anything during my stay.
There isn't good ventilation to change the air; the blinds had to be kept constantly closed to protect from smells and noises, and for privacy. You can hear everything from the other flats. I also didn't find the place to be properly cleaned to my standards: bedsheets and towels were clean; shower, toilet and bathroom sink had been cleaned; kitchen sink and surfaces had been cleaned. Still, when I opened the fridge its shelves were quite dirty, there was a weird smell in the kitchen and in the bathroom there were hair and body hair from other people (for instance, in the handle of the sink closet)! It seemed also a bit dusty is some areas (I am allergic to dust mites, therefore dust and hair laying around are not good for me). The whole place also needs a generic deep cleaning, as well as some renovation (there is a weird stain on the wall of the bedroom). Also, the water of the toilet runs all the time.
I also suggest to give to each guest an extra matt for the bathroom floor, as not everyone likes to walk barefoot on the floor after shower (and it's not clear if the matt at the sink is fresh or used for several guests).