"No road rash for us! We are experienced riders; own our own Vespas, and ride a Harley."
Unfortunately, being careful and experienced riders is no guarantee against the stupidity of other drivers. In my experience responding to motorcycle MVI's, these are often not the fault of the MC rider.
To answer your question, I have had experience with emergency medical services in Italy, after injuring my leg. Everything was handled well, although at the time the initial part in ER seemed a bit chaotic. My limited Italian skills were really pushed to the limit. The injury prevented me from flying so I had orthopaedic surgery and spent a week in hospital. The care in the surgical ward seemed to go fairly well.
In terms of billing and costs, I imagine that will vary to some extent depending on what type of travel medical insurance each person has..... coverage, exclusions, deductibles, etc. Although I had never used it, I found that my policy provided great coverage, including all medications required once I left hospital. Once I had notified them of the situation, they had their rep's in Italy handle everything and I didn't have to pay anything. They even arranged a chauffeur driven limo for transport from the hospital to the airport, and one night in a posh hotel before my flight home.
Since I was travelling alone, I found that my most valuable asset was my cell phone, along with a cellular roaming coverage plan. It was critical in notifying and keeping in touch with family, the travel insurance company and also my travel agent, as she had to cancel and then rebook my flights. The TA also dealt with the airline medical department, as without their clearance I wouldn't have been able to board a flight.