ATT blackberry did not work for me, at least not with a POP mail account. It may work with the Blackberry server e-mail though. I had no problems with text or regular telephone except for the bill. I really don't know how much an international plan saves you, I've got it and the bills I've had would stagger you.
Something interesting was that I could not dial a number manually but I could call by using my phone book.......strange.