Absolutely recommended!
We stayed at Eloisa and Elsa's apartment for 3 nights and everything went great. The location is very central, you can go pretty much anywhere on foot, and it's still near a metro station for longer trips (like to and from the airport).
There are 4 supermarkets very close, as well as loads of restaurants, pharmacy and things like art expos. Basically everything you need is close.
The apartment itself is in great condition, small but perfectly enough for a couple. Good hygiene, good wifi, good utilities. It's on a 4th floor with elevator and it has a lovely balcony.
The hosts are very nice, Eloisa was there to welcome us, showed us the apartment and also gave us A LOT of great tips about transportation, restaurants and things to visit in Madrid. She was also available for us to contact if we had any issues.
Would definitely stay again.