We stayed in the Nobile room and as others have said, the 360° views are astounding! The tower, the top of the duomo, the countryside in the distance, the city rooftops were all picture perfect.
The room is spacious, the bed and pillows were very nice, the heated floors were a nice touch. Going down the stairs for the bathroom could be challenging in the dark so the motion light on the way down was very helpful. Bathroom also is spacious and has heated floors, although the sauna takes up quite a bit of the space. There are a few maintenance issues with the shower, but it was quite large.
Check-in is a little unusual as you need to be prepared to call to have the lower door unlocked when you arrive. However, once you are in the outer door and climb 4 floors there are instructions in a key box for the rest of the stay. There arent really any check out instructions though so make sure you ask ahead of time if you plan to leave before 8am.
Overall, we very much enjoyed our stay in this unique room and look forward to some day returning!