You certainly can't go wrong with the Duratracs. The companies that run the ice roads up here swear by them for their pickups, so that should say something about how well they perform in snow and ice. They're really decent on rock and mud too, and they're quiet and have good road manners. The only complaints I've heard about them is that they tend to wear quicker than other tires (which is pretty common for winter tires in general, since they use a softer rubber compound that keeps a better grip in low temps), and they have weaker sidewalls than most off road tires (the "E" weight rating has a three ply sidewall, while the lower rated ones are only two ply).
I've yet to try out the KO2s, but they are a much newer design that first came out a year ago. They are very comparable to the Duratracs in most respects, but they're also advertised as being very durable and having excellent tread life. The only possible disadvantage (if you're considering this and it's legal in your area) is they aren't designed to be studded like the Duratracs are.
You might also want to take a look at the Nitto Exo Grapplers as well. They are another new winter rated off road tire that just came on the market last year, and they are very comparable to the Duratracs in design, strength and tread life, etc, and they can be studded if you need it too. Mel even used them for a race last year, and it sounds like they worked really well for him in the rock and mud. They don't have as wide a variety of sizes available though, so I'm not sure if you'll be able to get them in the size you need.
There are several people on here running those tires. I haven't 100% decided, but I've narrowed it down to the Exo Grapplers or the KO2s. The newer tires seem to have a bit of an edge on the Duratracs.
The only other winter rated off road tires I know of are Toyo's Open Country C/Ts and some sizes of General Grabber AT2s. I really haven't seen much about those review wise, and I don't think anyone on here runs them either.
Just curious, what part of the country are you in? Do they salt in your area?