I have had my Subaru for 9 months now and love it just as much as the day I bought it. My decision came down to the Mazda 3 and Impreza, and I definitely made the right choice. This car gets me through North Dakota snow and blizzards with no problem, excellent traction and stopping power on icy, wet and dry roads. Good ground clearance. I wouldn't mind 40 or so extra HP, but it is very capable. Always starts even on the coldest days. MPG averaged 25-30 last summer but is <20 in winter. But, I would expect that with any vehicle.
My favorite thing about my Impreza is that I can drive for hundreds of miles and never see another car exactly like mine! It is so unique, and even though it is almost a year old, heads still turn as I drive down the road. I purchased the rubber floor mats - a must in the winter - and splash guards.
A bit more power ... but really that is not a big issue. I can't think of anything major I would change. Standard heated seats would be nice, but not necessary.