The positives: Fantastic central Sol location, with bars, restaurants and shops on your doorstep. This does mean it gets noisy at night but the apartment is very sound proof when the windows are closed!
The apartment was sparkling clean and beautifully decorated with everything we could need and thoughtful touches like a Madrid map and a bowl of sweets. The bed is super comfy And the shower has plenty of hot water.
The negatives: the apartment shares a budkng with a youth hostel (which isn't clear from the listing) so there's a LOT of comings and goings and noise. The interior noise in the building kept me awake both nights (though if you're a sound sleeper, you should be fine - my other half was!) There was also construction going on with drilling, which was very noisy in the morning!
Besides the building noise, we loved our stay and the check in was so efficient. The apartment is a perfect place for access to exploring all Madrid has to offer!