My spouse and I stayed with Jesus for 4 days and had a perfect time. The apartment is in a semi-basement but has windows that get plenty of sun in the morning, and the place is spacious and furnished with everything we needed. Communication with Jesús (in Spanish, though I believe he also speaks English) was always quick and clear. The apartment doors use an online system to open which takes some getting used to, but once you learn the system it's pretty straightforward.
Otherwise, we really enjoyed the neighborhood for its no-frills, authentic feel; it features a few small cafeterias and bakeries, and a huge supermarket about 5 minutes away. We especially loved Juca, a cafeteria near Batán metro station. If you want to visit the sights in the center, you're about 30 mins away by metro from spots like Puerta del Sol.
I'll definitely stay here again next time I'm in Madrid!