When I was in Venice on business, I used all of these scooters (except the 'Wheels', which to me looked silly; I could pick up an electric bike, which were also everywhere, if I wanted to sit down). All of the scooters I used (the same ones in the article) worked fantastically well, I never hit a geofence or had a problem finding one when I needed one, and they are all amazingly cheap.
I never got in or witnessed a crash; the scooters don't go fast enough that falling off is a big deal anyway, based on my experience having to hop off one when I got myself into a pickle.