I think they are both superb cars. We were looking at both when we bought a newie in 2008. We found that we got more for our bucks with the Rolla, but I imagine the Mazda would have more guts. The rolla has a lot of storage space and that was a plus, and we liked the 'groovier' interior so that's what we went with.
I agree that it'll just come down to what feels better when you take them out for a drive. I've not come across anyone who's said a bad thing about either car.