As many of you know I was all about the STi when it was first announced until the time we finally got one delivered in Maine. I never even considered ever buying a Mitsubishi and hated what the EVO looked like in pictures. The only thing that sounded better was the available sunroof and the rear wiper. Two things that wouldn't make me switch over to the EVO.
I still haven't driven an STi so I can't speak about how it drives, except from what I've heard and what I've seen at AutoXes, NASIOC, and EVO/WRX g2gs.
The argument between the two has been going on and on and on and will never die even if they stop making these cars. It is definetaly the same as arguing about a Camaro and Mustang except that the EVO and STi are very much more similar.
All the complaints I've heard about the EVO I rarely agree with and I've noticed that most folks that make these complaints haven't even driven one, they only take what a magazine says about them as fact.
All I can say about the EVO is that it's my daily driver, in 7 weeks of owning it I've put close to 8K miles on it and haven't had a single problem. If you ever read my posts about my SVTF, you'll know how picky I am about my vehicles. I've owned a subaru in the past, and it wasn't this reliable, and some STi's were released with a detonation problem, and I can't respect the flapping hood scoop or the flapping wing. So for me the initial quality of the EVO outweighs the STi, but long term is what matters, and that remains to be seen.
The only negative I feel is the strength of the clutch, you really have to know how to drive a manual for the clutch to last. It hates 5K and above launches and let's you know only by the smell of a burnt clutch the lasts very long so you don't forget.
Every magazine says the STi is smoother, more mature, etc. and when I read that I said that was the car for me. After driving the EVO for almost two months, I can't imagine driving a car that doesn't communicate as well as the EVO does. Because of this communication through the steering wheel and the susupension you know exactly what the road is telling you, you can drive it faster and better because of this, with the STi you've got to be a better driver to get the same performance out of it, in the long run, that may be more rewarding.
The aftermarket for the EVO is huge, the STi will take a while to catch up. Yes 2.5 Liters will get you more than a 2 Liter in the long run, but if you intend to use either car as a daily driver, how much horsepower do you really need and would you be able to drive it safely.
In the end drive both cars, the right one will speak to you. Either way you won't go wrong, both will leave a lasting impression and a big smile. If you like the looks and style of one better than the other, than there's your choice, just a word of warning, don't go by pictures, both look vastly different in person.