We stayed in the Vivaldi Suites for four nights at the start of September. This was our favorite hotel of our 12-day 11-night trip through Italy. The Vivaldi Suites are away from the main hotel, a short walk down the street in an apartment/condo type building. They are entered via two large wood doors between a couple of shops. It was neat - like we lived there!
The room was wonderful, wood floors in the bedroom, large plasma t.v., couch, desk w/laptop to the Internet (although couldn't check our email in the States - don't know why). The bathroom was beautiful, too - enclosed shower, jacuzzi bathtub, elegant fixtures (had trouble getting hot water a couple of times in the shower, though). It was nice & quiet with the windows and shutters closed, but it didn't have a balcony and just overlooked the street (which was better than our other hotels which overlooked walls :)
The rooftop bar was nice, the breakfast tray was big & served in your room just a few minutes wait after calling (of course, our room was right next door to their kitchen). For a couple of mornings, I had to use my limited Italian since the room attendant did not speak English, but that was fun, and she was nice.
British Airways had lost our luggage on the way there (Rome was our first stop). The front desk clerks were very nice & helpful. They helped us call the airline a couple of times. My husband received his bag after the second night, but I did not receive mine until we got home - it had been three weeks since I had seen it last! My advice - carry on all luggage!! Most of the salesclerks in the shops were VERY unfriendly to me - which was disappointing, since I could have used a smile as I was very sad at not having any of my clothes (luckily, I had all of my non-clothing personal items in my carry-on bag).
Anyway, I think a good rule of thumb is what another tripadvisor said - don't buy the cheapest room in a hotel - go at least midway or live it up with the most expensive. This is what we did at Hotel Mozart, and we loved it!