I'm going to go against all the people saying the Mazda has the better MPG by far. I have the 2012 Impreza, which gets 1mpg less according to the EPA, and I can EASILY get 42mpg highway on flat ground going at 55-60mph even without cruise control. And I haven't even gotten a throttlehappy tune, people are reporting a good 5-10% increase in fuel economy with it. Who knows, maybe I could get 45 or higher.
AWD is not just better for snow/dirt, even at 1/2 throttle most FWD cars will spin their tires on pavement from a stop and wear them faster and potentially cause an accident.
The biggest advantage of the Subaru is not being built half by Ford, one of the least reliable brands in the world. Mazda is partially owned by Ford, and many of the parts are Ford. The Subarus really don't have many issues except the oil burning on some engines, which is a small percent (some sources report 1 percent of the vehicles).
One other thing is the Subaru is easier to do maintenance on yourself in pretty much every way. That Mazda has a lot of the stuff hidden under engine covers or under the car. With subaru, when you open the hood, everything you need to do regular maintenance is right in your face.
edit: oh and CR rates the 3 as the least reliable Mazda model.. something to think about.