The boot blankets are definately worth it. I put them on as soon as I get up in my stand. Just don't get too excited after the shot and walk around in them. The sticks under the snow will puncture them.[:'(]Nothing a little duct tape couldn't fix.
Craigster, I put them on BEFORE my feet get cold. 7 degrees, wind chill below zero and still nice and toasty. Maybe you need better boots, you have to start with something, they only add to the comfort.