Here's an interesting read for you to compare trade offs:
performance a/s vs a/s vs. performance winter vs. winter.
http://www.caranddriver.com/comparis...mparison-tests
Look at the chart for each tire and note the stopping distances for snow/wet/dry. There are some big differences. For instance, in dry, the winter tire stops 30ft longer than the best--that is HUGE. But in snow, the winter tire stops 40 ft shorter!!!