I stayed at the Emperador for a few nights last year, and I liked it very much. I'm not familiar with the other two, though, so I can't say anything about comparing them. The things I liked about the Emperador were: nice, comfortable clean room that wasn't overly modern (I prefer hotels like that), huge clean bathroom, beautiful lobby, polite, attentive service, good breakfast, excellent location, right in the middle of things. Some friends of my parents visited Madrid maybe two months after I did, and stayed there as well. They were extremely pleased with the hotel. Good luck with your decision!