It is convenient to use both their high-speed Strelka and regional trains. I traveled from Milan to Bergamo and back on Trenitalia in 2016, from Verona to Paris in the same year via Milan (Trenitalia is a co-owner of Thello trains), from Verona to Trento and back, from Bologna to Verona in 2019, to Verona and back most recently last year. Always on schedule, comfortable trains (if you take the express, not the regular one), well, except for the night Tello - similar to the Russian intercity.
I visited the Trenitalia ticket office at Milano Centrale a few days ago, and I was lucky to deal with Ms. Maria Grazia. She was incredibly helpful, knowledgeable, very friendly and maintains positive attitude. She found the right tickets for me and my family for the right price I was looking for.
I wish her all the best, and I congratulate the Trenitalia Human Resources Department for recruiting a fantastic person, such as Ms. Grazia, into their professional team. Thank you for your time.