Very nice appointed apartment, and very good use of space. Great location.
The air conditioning was ridiculously good. Being an American who has lived in hot U.S. cities, I'm often underwhelmed with A/C in Europe. Not only was the air conditioning central air (rather than the ventless units), it really did a fantastic job of keeping the apartment a reasonable temperature when it was 90+ degrees outside. Much better than any apartment I've rented in Europe, and much better than I'd expect even at a fancy hotel in Europe.
Just one heads up: the elevator isn't all that functional (it is a medieval building after all). It doesn't reach the ground floor, not does it reach the floor of the apartment. If an elevator is essential for someone in your party, I would hesitate... And the same probably holds true for most apartments and hotels in old buildings.