I have stayed in many apartments in Madrid and this is one I would consider again in the future. It was clean and well-presented with decent sized rooms with A/C and cupboard space. However, there was one room with en-suite with sliding clear glass doors so only suitable for a single person or sharing with someone you know extremely well as there's no privacy from the shower or toilet.
We had an issue on arrival. The automatic entering system didn't work. Raul was contacted and was unable to resolve over the phone or when he arrived a while later. Only when another set of keys arrived were we able to get in.
Be aware that there can be some outside noise through the night. Our arrival night was the San Isidro Festival and there was a lot of noise until around 04:30pm - this could also be the case at a weekend. The rest of the stay was better although bin lorries seemed to come at all hours of the night.
Nevertheless, the apartment is in an excellent location, close to Quevedo metro station and a pleasant amble into the centre. The lovely Plaza de Olavide is close by too. Raul kept in touch too with emails.
As I said earlier, I would consider this apartment in the future.