Apartment is steps away from Plaza Mayor, which is a very central location. The apartment is very nicely remodeled and has everything you might need. It's very pretty. The air-conditioning, Internet and hot water heater all worked really well and were welcomed luxuries after more than a week of travel.
The only down side was that there was a lot of noise in the stairwell on the Saturday night, almost through the night and the smaller bedroom (with the one double bed) has a window onto the stairwell and it was a bit too noisy. There is a sofa-bed in the living room though, so there is somewhere to move to. Other nights were ok.
Overall, I highly recommend the apartment. It's in an historic building in a great location and it's clean and remodeled. It's very nice. Host and hosts helper who let us in, were good. Make sure you check out other neighborhoods too because the immediate area is so touristy. Everything is easily accessible though.