I stayed in April 2021 at Helena's apartment with a friend of mine. We each slept in one of the bedrooms. This was the perfect setup for us: each one had his one bedroom and bathroom.
We were very pleased with the apartment.
The apartment itself is gorgeous, with very high ceiling, tastefully decorated. A beautiful space.
The building is very nice too.
The location is hard to beat: in the heart of the lively La Latina neighborhood, but in a quiet street. You feel at the center of the action but yet in a very quiet place. Very easy to go to many other parts of Madrid on foot, in 10 to 25 min. We were basically walking everywhere.
Communication with Helena and Alex was great: they're both super responsive, both at the time of the booking and during the stay.
The place is clean, has full amenities, good internet. I had to do a bit of work from the apartment (needing to connect to a VPN etc) and the connection was largely sufficient.
I would certainly recommend this place, and will certainly consider staying there again when next in Madrid.