I had an excellent stay at Simon & Arturo’s place. They were incredibly nice and very helpful. The apartment is in a relaxed neighborhood, 15-30 minutes north of all the hectic touristy parts (20 paces to Columbia subway), still with easy access to it all (€13 taxi or uber off peak - but be careful of uber price gouging for busy hours - €48 at 9pm on a Friday night to the outskirts of the city center (taxi was still only €14). There was a nearby gym that offered 1 week memberships, with a pool (open swim 3x a day), boxing heavy-bag, free weights & machines, cardio machines & spin. The private bathroom attached to bedroom was really nice to have, as was the private bedroom entranceway to the huge garden balcony. I highly recommend Simon’s apartment! I would stay here again if in Madrid.