Being new to Madrid, we wondered about the location when we first arrived. However, once we had settled in and started exploring it became clear that the location is ideal in that everything is within walking distance. Furthermore, as the apartment is not in a "touristy" area, we felt "at home" and enjoyed the close-by restaurants etc frequented by our neighbours- all simple, friendly and fun.
So, I would recommend this apartment for a couple (which is what it's rated for anyway) as it is cosy. The apartment was immaculately clean and the decor pleasant. There are 4 flights of stairs to negotiate, so bear this in mind if you're not up to lugging baggage.
Finally, our hosts were really responsive and we could not have asked more of them.