If you live in any of the snow states, these tires are a must. It transformed my little open diff fwd economy car into a snow hungry monster. For light snow, I can drive pretty much like it's dry. In heavy snow, I can still plow through with great stability especially when changing lanes on the high way.
Recently my area had about 18 of snow, and my car was able to plow it's way from my driveway onto the street without any problem. My neighbors thought my Honda had awd..
No your AWD with all season tire will not out perform a 2WD vehicle with proper snow tires. You may able to get off the line a little faster, but you'll just end up in a ditch faster. Blizzak offer you better traction ALL around. Acceleration, braking, and cornering.
I'm on my third season and I still have over 9/32 of thread left. It's going to be a while before I have to replace it.
There are down sides, such as dry response and grip. You feel instantly the soft sidewall of these tires compare to AS or summer tire. I got white knuckled once taking a corner aggressively like I would on my AS tire. I only gave this tire a 5/7/6 in the dry category.
However, just looking at the snow performance alone, I give this tire 10/10!