This place is every bit as incredible, not to mention clean and comfortable as it seems in the photos. The location is obviously amazing and it defies all reason that you are able to stay right there at the foundain. The sounds of the fountain are easily welcomed in or blocked out by opening/closing the very effective and modern windows.
Like any Airbnb there will be small things that could be improved upon, like a bit more thought in the layout (counter space) and provisions (bath mat) in the bathroom. Then some things are just out of anyone's reasonable control, like stinky old pipe systems in bathroom (not uncommon in Italian homes and buildings).
Alessia has done a wonderful job decorating and keeping the space classic, modern and open. Little pluses like the espresso machine with coffee pods are great.
I can't imagine how this experience wouldn't result in a 5 star review - even the 40 min wait for Alessia (due to classically terrible traffic) is a distant memory.
But really, Alessia has done a great job as a host in setting this up and there is nothing that can detract from this location even the overwhelming crowd that grows throughout the day only confirms that you are lucky and this is a special place.