Enjoyable 3 night stay in late June. As noted by many, location and (stylized modern industrial) aesthetic are great. Finishes are more upscale than many Airbnb stays,
Central air conditioning was a nice surprise, but thermostat was set and locked at 21C. Hot air rises.
Wood shutters do a good job of blocking light.
Mattress is not memory foam as one review states. It is foam, but a more upholstery grade (sleeps hot and very firm.)
Parking really is NOT free or on site. We spent an additional €84 for 3 nights at a garage. The included street parking is not accessible until after 18.30, and would really only be suitable for a small rental car.
The main bedroom is in the upstairs loft area (hot air rises). The only toilet is at the entry, ground floor. Night time bathroom trips require using stairs.
Structural beams flank each side of the bed. Anyone taller than 5'9" or so will need to duck to get into or out of the bedroom.
Location is ideal for seeing the sites, including the Vatican, as well as many, many, dining and drinking options.