First off--great management company, attentive in every way. Fantastic location that cannot be beat. Close to everything and metros. I was surprised how quiet this apartment was despite the busy location (don't be scared off by possible noise--it's not there).
Hated the low ceilings/beams. Doorways are only 1.68m (5'6") or so. I constantly hit my head and couldn't stand up in 90% of the bedroom. Apt is accessible only by 21 step spiral staircase. If the staircase isn't apparently a hindrance, remember you'll need to carry luggage up/down.
Wonky (though from their perspective ingenious) main access to building through an app that takes getting used to. It worked eventually but shouldn't need a video call to figure it out. (Set up a you-tube video, guys). No instructions on washer/dryer (?) or coffee maker (which, in turned out, needed disposable cups--not included). It would have been helpful to provide one cup and a map to the store where we could get more. Water heater didn't work (minor problem and easily fixed had we bothered to contact management).
If I sound critical, please be assured I'd stay again because of location and the Charming Concept management. Although I'd attempt to get the apt below this one (Fuencarral I) as it wouldn't have the spiral staircase.