I initially purchaced 2 tires for the rear after the wife made an unepected trip into the ditch with only a dusting of snow. The discount tires I had replaced the oem ones with were sub-par when it came to snow and wet traction. With just the 2 tires on the rear, the traction and handling of my Trailblazer improved dramtically. Needless to say I was impressed. Before the next winter I purchased 2 more. The handling and ride improved 10 fold. My SUV rode and drove better than it did new. I have about about 50-60K on these tires now and my Car has 162000 miles and I'm still impressed with these tires. I've lost a little bit of wet traction, but it's insignificant compared to my previous tires. The front tires have worn a little choppy, but I haven't rotated like I should. Plus, I've never done any drivetrain and suspension repairs either. I'm expecting I'll get another 15-20,000 on this set.
These are the best tires I've ever owned. Not a good job, Firestone, but a great job!