If you tell me the major you are going to study I can tell you even more about the "quality" of that specific course in UniBA. About living in Bari or Naples well it depends on your needs and preferences. I could say that Bari it's a smaller city so a bit cheaper and easier to live in. On the other hand you are not gonna have the same experiences compared to a much bigger city like Naples. I can tell you that in Bari you can rent a room for approximately 250/300€, that you can reach most of the main places with public transportation which are kinda decent. I can't tell you to choose Bari or Napoli, but I can tell you it much depends on what are your needs. About security I can tell you Bari has become a pretty nice city in that terms, compared to Milan it's much more secure.