I went from a 2008 STi to the 2010 EVO X. STi had a much more pleasant interior, however the seats in the X are amazing. SSS package is a must, and is well worth it. The biggest complaint is overall build quality compared to the STi and the lack of space. Buttons feel cheaper, seating position is not great, even though the seats are amazing. You cant go wrong with either car, but if you want the closest thing to the X you would need to buy a 2011 STi, as 08-2010 don't compare. Paint quality seems to be better then the Subaru, along with less turbo lag (even though its .5 L smaller motor). Probably the biggest difference is fuel economy. The 5 spd is to short and gets 8mpg less the STi got.
Handling out of the box, engine response, seats, and aggressive looks. This car is a blast to drive, always in power, and phenomenal brakes. The SSS package is a must, and the 2K more is well worth it.
Better overall fit and finish. I got the car brand new and it had small rattles pulling off the dealer lot. Also after 600miles the MAF sensor failed, which is a common problem and got replaced with a upgraded unit by the dealer with no questions. Cheap feeling buttons, and very poor fuel economy.