If you're looking to buy these tires with winter conditions in mind, you'd be better to cross shop the KO2s against Nitto's new Exo Grapplers than their Terra Grapplers. The Exo Grapplers are winter rated, Terra Grapplers aren't.
I've been looking at both the KO2s and Exo Grapplers myself, and it looks like a really tough choice. I'm leaning towards getting the KO2s right now simply because the Exo Grapplers don't come in 37s, otherwise I might opt for the Nittos. Both are brand new as of this fall and have similar design characteristics. Both are supposed to have long tread life, strong side walls, good road manners, and perform excellent in snow and ice as well as good in mud, rock and other off road terrain. The biggest difference on paper is that the Exo Grapplers can be studded. Since I'm just going off reviews too, I'm also keen to hear more about these from people who have run them.
OverlanderJK suggested the Duratracs, and they're another good one worth considering. They've been around since 2009 or so, and they are a tried and tested (and until last fall, the only) winter rated off road tire. The guys who run the ice roads up here swear by them for their pickups, so that should pretty much say how great they are in snow and ice. Like the other two, they also have good road manners and are very good in mud and rock. The two biggest complaints anyone has had about them is they have a shorter tread life and weaker sidewalls than most other off road tires, and those are two points the new Nittos or BFGs should do much better for if they live up to their manufacturers' claims. They can also be studded.
Toyo also has their new Open Country C/Ts that came out last fall as their winter rated off road tire. I haven't heard much about them yet though. I know they are available in Canada, but I'm not even sure if they're sold in the US yet.