I think that most people know why they are buying a subaru. I'm not going to recount the obvious pluses and minuses, but after 20 months of ownership, I'll mention the small things that stick out.
The efficiency is great, considering it's awd. However, the car is very sensitive to hilly driving. I've never hit 36 mpg on a trip (32 MPG lifetime) and I think this is because my commute has lots of rolling hills.
The interior is not quiet. I never had expectations for a luxury car quiet interior, but I do have very good hearing. I've had the chance to rent about half a dozen cars over the past few months, and my Impreza sticks out as being really loud on the inside at moderate speeds, even louder than smaller, lower priced cars. I do a lot of highway driving where this is really apparent. It wears on you after a while. While I could tell from my test drives just how loud it was, I never understood what living with this would be like.
HVAC is loud and has to be cranked to really feel it.