Pro: It's a very stylish place, with all what you need in a quite small space. Internet work very good, all is clean and nothing is missing. Security is good, and the checking and checkout process autonomous. (But the hosts can welcome you also if you wish it). They respond quickly, send us a list of places to see, tips,... and nice. The location is central and quite, as very close to main streets but no directly on them.
Con: The only real con would be the size of the window, very small, so you have to accept not to have daylight in the apartment.
In synthesis, a perfect place for 2 or 3 nights in Madrid, for one or two persons. If you plan to stay more than 3 nights, I would go for a larger space, otherwise David and Bea's place is really good.