We visited Madrid for about 4 days - and Conchis Appartement just made it easy for us to enjoy our stay. The Appartment is in the middle of Madrid. There is an 10 minute walk to the plaza mayor - even less to "sol". to summon it: We have reached all sights, including museo del Prada an the botanic garden on foot.
The only fly in the ointment was that you can hear the cars and trucks who pass the small street next to the apparentment all night. So if you have a light sleep, just bring earplugs with you.
For us it was the perfect place for our Madrid tour and we'd love to come back soon.