I've never heard of any major reliability issues with the 2. That's part of why I bought one. That said, it's a little Japanese car. Properly maintain it, and it'll take care of you for a long time.
I've never owned anything that wasn't a Mazda. Every one I've had, that was properly maintained by it's previous owners, has been reliable. (the 2 is my first brand new car) Obviously, with the older ones, small bits broke or wore out rather often, but the major components were just fine. I don't keep buying Mazdas for no reason.