I have stayed at this apartment for a weekend break in Madrid.
The place looks exactly as described in the website and it is clean and tidy. The host was very flexible both for my check in and check out, and was also replying quickly to any communication during the whole process, so I always felt attended. All elements in the flat were working properly, including heating and dishwasher, with no incidents at all during my stay. The nearest underground station is within a short walk (5-10 minutes) from the apartment. There is also a bus stop literally by the front door.
This location is ideal if you do not want to be far from the main areas of interest, but you also want to be on a quiet area to get some rest at night. There were no noises from the neighbours of from the street (the apartment is located on a third floor, and the lift was working properly).
I would have no hesitation in recommending this apartment for anyone visiting Madrid and looking for a quiet place to stay.