I couldn't recommend our stay at Plaza Espana enough - we had originally booked a two-bedroom apartment but because of changes in our itinerary, had to switch to a one-bedroom standard unit. The service staff was impeccable in organizing our re-booking and in the check-in/check-out process.
The apartment was spotlessly clean and well-appointed with everything we needed for our stay including a full kitchen and washer/dryer unit in the common area of each floor (much appreciated since we were in Madrid after 8 days of travel around Spain!) The apartment location is also great and we walked to many of the attractions in central Madrid. A lovely stay, and one that I would strongly endorse!