I've always been a fan of mud tires, running KM2s on the 40 now, but on road ice/snow, no bueno! Then, I found out about siping and I'm a huge fan. Solved my on road issues, even helps with rain driving. It really helps those things grab that Moab slick rock too!
I bought some Cooper Discoverer AT's for my latest project but they are brand new and I've never driven them before. If they don't give me what I need, I won't hesitate to have those suckers siped too! I've been told it reduces mileage but its not a daily driver so that's not a concern for me.