Funny, my KM2s rock in snow and ice too. I've got about 34k miles on mine now, still more than half tread. They are getting less effective (duh) as they were, but still work as well as/better than the other mud tires I've used.
They are light, they do flatten out well when aired down (pro or con depending on use), wear and ride well, they are quiet (for an M/T). If you want more siping, by all means get them siped. I had a couple other pairs of M/T tires siped and they were incredible, despite a little bit of chunking from lots of gravel. The tire stores in Kentucky don't have a clue what siping is though, unfortunately.
The main thing that I don't like is the sidewall, for use on a heavier truck. They are fairly thin and offer little protection to the wheel, and side stability is not what it could be.
I'll probably go with the Toyo M/Ts next time for the stronger construction, although I'm not excited about the weight.