1. Price- STi will likely be more expensive than the EVO. Expect no more then 33K though.
2. After Market- Well, since it's a DSM the EVO will have a stronger aftermarket. However, the Subaru aftermarket will continue to grow and become as strong if not stronger in the future IMHO.
3. Quality- Well, Mitsu is known as the American car company of Japan if that means anything to you. Subaru isn't a Lexus either, but the overall quality is much better IMHO.
4. Performance- If it was Japan or Europe- the edge would go to the EVO slightly. However, this is America and we are getting the best Impreza EVER built (except for the WRC car

). The STi has 30+ more Horsepower, a 6-speed transmission, more technology in the AWD system, and bigger rear brakes.

The STi US-Spec will wipe the floor with the US Spec Evo, plain and simple.
5. Resale- See #3 above.
All IMHO...