Edit: This morning I got the chance to test out the tires in about 6 inches of snow and slush on the roads. Snow mounds from plows. Cross grooves in suburban neighborhoods. Nothing was able to stop me. Even passed someone on a 2-lane road.
If you live in an environment where it snows and don't have snow tires, get them now. Take it from someone who never felt they were worth the expense. They are absolutely worth the expense.