Trenitalia or Italo?

Just check the stations that they use. Some of the stations are not center. In Rome, Italo does not use the main station, Termini. Italo is a newer and newer rolling equipment. I would go with schedule and price.

Joe,

As Frank mentioned, you'll need to check the stations for each leg of your trip. If you're comfortable using alternate stations in some cases, you could travel the entire time via Italo.

In the same situation, I'd use a combination.....

• Milan to Rome: Trenitalia from Milano Centrale to Roma Termini.
• Rome to Florence: Italo from Roma Tiburtina to Firenze SMN.
• Florence to Venice: Italo from Firenze SMN to Venezia Santa Lucia.
• Venice to Milan: Trenitalia from Venezia S. Lucia to Milano Centrale.

Happy travels!

Italo is better in my opinion, though they have a smaller network. They serve your first journeys but not Venezia-Milano. Italo trains are newer and more high-tech (at least until Trenitalia phases in its new HS fleet), and being a private enterprise (instead of a bloated state company held hostage by unions and bureaucrats) they have developed a reputation for better (though not perfect) customer service.

Milano Pta. Garibaldi is actually a better located station than Milano Centrale: closer major areas of interest and with a much better surrounding.

Roma Tiburtina is 2 easily accessible by public transportation as well.

In Firenze and Venezia both rail companies use the same stations.

I took both last year and considered comfort to be equal in second class, so I would also choose the combination of schedule, price, and arrival station that fits you best. Both have advance discount tickets. Rick lists quite a few hotel recommendations within walking distance of Roma Termini station, for instance, so a direct train to that station makes sense if you're staying nearby. Similarly, you could judge whether Milano Centrale or a different station is more convenient to your Milan hotel. All are served by metro.