By all means, stay at the Hotel Alfonso XIII for as long as your wallet or your points hold out. We stayed there two summers ago during a 17 day trip through Spain, including Madrid, Toledo, Jaen, Granada, Cordoba, Sevilla, Oropesa, Segovia, Rascafria and mentrida. Stayed 2 or 3 nites at the Alfonso, and it was spectacular. We used an award stay, and were still upgraded to a very nice room, and treated very well as Starwood Gold. Nice amenities, and great staff. The breakfast buffet down in the courtyard is certainly one of the best breakfasts I have ever had. And being in Spain on a hot day, touring around the nearby Sevilla sites like the Reales Alcazar and the Cathedral and the bullfighting museum, and then being able to relax and refresh in the Alfonso's great pool, was fantastic. Surely one of the great hotels in Europe.
(If you want any information on other places in Spain we traveled, feel free to e-mail me).
Djlawman