Honestly....here we are again. Even though the Mazdas have their share of little problems (all cars do), I would much prefer the overall quality of the Mazda over any Subaru or Mitsubishi.
When have you ever read where there weren't issues over a Mitsubishi product. Plain and simple; they are not very reliable cars. Check any consumer report. They ain't that good! And I don't imagine, the EVO will be an exception. I would bet that is going to be a problem prone car.
Subaru? Well; I like more than the EVO. I think that STi is damned sharp; whereas the EVO (to me), looks like s***. Again; that EVO front end is horrid!! Subaru quality has improved over the years, and I think they are nice cars. How will they be down the road after a year, 2 years, etc...? Who knows.
Between the two; I choose the STi. I have read the tests, and they both have advantages. I will always give style a nod, when things are that close.
It's all subjective. It's all personal choice. A buddy of mine's friend in Knoxville just bought an STi for about $30,000. From what I have seen, that's less than the EVO. In Memphis, they are asking about $35,000 for the EVO.