I wore those same Keens for a winter and a half, loved them but like every other pair of Keens I've owned, they wore out very quickly. It's to bad too, I absolutely love the fit of their shoes but I rarely get more then a season out of a pair.
I've been wearing a pair of Vasque Snow Junkies for the last few weeks, and so far they're very decent. They want to lace up super tight with no effort, but so long as I keep the laces on the loose side they're pretty plush, with the capability to be very supportive if need be. Warm enough for high excursion, so far are waterproof, lightweight for a winter boot, and should last me longer then my Keens did.