When AdvanceTrac first came out I got to go on a Ford "ride and drive" event for sales people. We got to test out the truck with and without the system engaged, and the difference was huge. We ran them on a course and pushed it way harder than I would if it were my vehicle. We bascally beat the daylights out of it. (The Ford Tech guy said that they had to change tires DAILY)
The system is basically just stability control that applies brakes to individual wheels based on speed, steering angle and actual direction of travel to help guide the truck in the direction that you want to go. It should help you on slick and twisty level roads, but even with the traction control, you're not going to get up steep, slick hills the way a 4x4 would. Of course the system only works if the tires are in good shape.
If you're worried, pick up a set of "chains", I use the quotes because most of the "chains" out on the market now are actually cables of some type.