Live in Toronto, going through the same snow storm. Stock SEL tires (haven't gotten snow tires yet) and drove on unplowed roads. The TC comes on sometimes and does limit your power but i still passed other civics and corollas on the road. I wouldn't say it's any worst then any other car. Actually the civic driving in front of me with snow tires was fishtailing around and the focus was staying pretty stable, im assuming it's because it's a heavier car. Pretty happy with the winter performance so far.
2012 Sterling Grey Ford Focus SEL Hatchback