I had a stopover for a night before catching my flight the next day from MAD. The dude who checked me in was pretty chill, the internet speeds were good, I was able to get some work done. Its close to subway stops to get to both Madrid-Atocha (Railway Station: 20 mins) and Madrid-Barjas (Airport: 30 mins). The funny thing is the subway ride themselves are quick but you walk deeper and deeper through a maze of some of the the most amazing subway tunnels, deeper than any NYC subway tunnels I've walked through, it was pretty amazing. Would love to stay here again if possible.