We overal had a pleasant stay. The central location is perfect and the communication with the owners is great. The apartement is situated in an old building, so you can hear the people entering and above you. Probably that is in all the old buildings in Madrid the same.
There were a few things we thought could have been better: not all the lights worked, there is no waterboiler, there is no sinkstopper or washing-up bowl. Altough there is a hairdryer, it just works for 30 seconds and then has to recharge.
Tip: bring your own few tablets for the dishwasher because there is none.
Nevertheless, we had a fine stay in the apartment and in Madrid.