Moisés is a nice host, available and responsive to messages.
The flat is nice, new and almost exactly as in the pictures (although the bathroom is slightly older than it seems) but it is so dark you cannot tell whether it's night or day, so you need artificial light 24 hours a day. It was not mentioned in the description, so I was a taken aback when finding out.
I guess the constant lack of light makes the place humid: it was quite cold at night (despite being hot outside) and I found the sheets and some of my clothes slightly humid, too. What I found unpleasant was also a quite strong smell, probably due to humidity, that you particularly notice when coming home and being used to the outside dry air.
When I first made the bed, some of the sheets were stained. Luckily, there was a clean set as well and Moisés helped me with the matter.
The location is ideal: well served by public transport and about 400m from the Gran Via.
I wouldn't particularly recommend this place considering the abovementioned issues. It is a shame though as the apartment is pretty and and the hosts (I had the chance to meet Moisés's lovely partner, too) are nice.