It’s a nice flat in a quiet apartment building, and good for 2 people for a weekend. The kitchen was well supplied with the essentials and it was clean and tidy. It’s a good area too, and easy to reach everywhere in central Madrid on foot or underground / bus. You’re also very close to both the Reina Sofia and Prado.
As some others have said in there reviews, being an older building the sink drains can smell a little at times. Having only one air conditioning unit (in the living room) can be a little warmer at night too. Also if you like a firm bed, be aware the mattresses are both very soft. It’s a fair price though, and we enjoyed the stay.