i never understood the need for winter tires initially, as i had only ever used all season for the 20 years of driving before i bought my first set...now, i won't go without them...they are that much better...sure, accelerating from the lights is better, but to me, the braking and steering ability (to maintain grip) is worth every penny, and it is substantially better than all seasons.
oddly enough, a co-worker of mine is about to pick up his brand new FRS and purchased some premium all-seasons...i asked why he didn't get winter tires, and he said he would be fine without them...he previous car was a 2010 Subaru WRX, with winter tires...i don't understand that decision (not the car, the tires).