Most reliable airline for RT flight between FCO and Palermo

Hello, my husband and I will be flying round-trip from FCO to Palermo. We are trying to decide between ITA Airways and Ryan Air. Has anyone flown either of these airlines between FCO and Palermo, and if so, what was your experience? Since ITA is the successor to Alitalia, I am concerned about its reliability in terms of on-time departures, mechanical issues, etc. For Ryan Air, we'd purchase a ticket allowing for a checked bag so we won't be worrying about whether we can carry on our luggage.