Trenitalia have been great in my (limited) experience, from a couple of years ago:
- Dinner in the restaurant car on the Paris-Rome sleeper - delicious food, absolutely chaotic organisation. Went along shortly after boarding, tried to book a table (as recommended) - no one seemed sure what was going on and advised to return around 9. Duly did so, was sat down after a short while. Much shouting heard from galley, chef barges out with large knife in hand, puts it round the waiter's neck whilst having jocular banter, all the while whilst the train was bouncing around. Not recommended for vegetarians, IIRC the only option was meat-filled ravioli followed by veal.
- Go to get coffee on high speed service. Coffee is about a teaspoonful of excellent espresso in a paper thimble. I think cappucino was also available, and that was about it.