Location is really the best. Right in the city centre, could not be better. It was great that early check-in was possible in our case. Also you enter the apartment with a pin number so there is no problem with keys etc. if you are travelling in a group.
Only minus was double duvet on a double bed and not two single duvets, since if travelling with friends, single duvets are more comfortable. Street under the apartment is a bit loud during the night but I am not a type of a person, having problems with that. If I return to Madrid, this apartment will definitely be my 1st choice.