I put my new ContiExtremeContacts on two weeks ago, just in time for a blizzard. I drove about 300 miles at night on roads that weren't plowed. I saw one car go into a snow bank when trying to make a right hand turn. My car on my brand new Contis never felt so secure.
That being said, I think snow tires are a must if you get significant snow where you live. ContiExtremes are NOT snow tires - they are all season radials - which might be fine if you live south of the Mason Dixon line. They will do in a pinch but are not meant to be driven extensively all winter in snowy and icy conditions. Thats what snow tires are for.
