Because of a prospective labor strike that could frustrate our plans to travel from Rome to Naples a few weeks ago, we booked first class passage on Italo at Rome's Tiburtina station. (Tiburtina is new, about 4 metro stops away from Termini station in Rome) Italo offered an introductory price of E35 (about $42) each way for first class passage. The carriages are first rate, bathrooms clean and advanced, personnel utterly professional. The Italo departs on time and arrives on time: 1 hour 7 minutes from Rome to Naples (Garibaldi station). Its speed reached 300 Km/h. Included in the price is a snack and beverage service(including coffee and Prosecco). It's excellent. My comments are not intended to criticize Trenitalia, which we would have taken, if its staff were not striking.
Joseph, thanks for the info, lots of people are interested in the new train company. Tiburtina station has been around for a long time, it's been redone a few times (including after a fire that shut it down for several days in 2011). Italo tends to use secondary train stations, but there's usually an easly link to the city center or to the main station (separate ticket needed).
Italo uses the same major stations in Bologna, Firenze, Napoli, Venezia. While Milano Rogoredo is not helpful for tourists, the other station, Milano P. Garibaldi, is actually much more convenient for people for whom Milano is not a transfer point but an overnight destination. The surroundings of P. Garibaldi are much, much better than what is to be found around Milano Centrale. One of the best areas of Milano is just a couple blocks away. Italo has getting very good reviews for its service. I love rail competition.