I just try and remember what my old buddy Mike used to say - "Go in in 2WD, get OUT in 4WD". If you go IN in 4WD and get stuck... well, you're stuck (unless you have a winch).
Last month we had the worst ice and snow storm in 40 years. 6 inches of snow, followed by 1/2 in of ice, followed by 12 inches of snow.
I was out in the Tahoe, and tried to get up a hill. Slipped like crazy, slid back down the hill. Engaged the floor lever in 4LO, and waited for the thermal actuator to work. Thankfully, it did. I started crawling up the hill, and 1/2 way up, I started to slip again. I rolled down the windows and stuck my head out. What I saw was that one of the front tires had no grip and was spinning, and one of the rear tires also had no grip and was spinning. Although I have limited-slip on the rear, it appears to make little to no difference in this case. The truck was just stuck. I had to slide back down the hill, and WALK up.
I like the simplicity of the basic 4WD on our trucks. I know if I had taken the time to chain the tires up (which is a colossal pain with 33" tires) I would have been fine. My wife's all-wheel-drive van actually did better, as it dynamically adjusts to send torque to the wheels with more grip. It is a WAY more complex system, and will be a bear if and when it breaks, but it does do a LOT better in these situations.
In this case, I found another way up the hill with the Tahoe.
Off-topic, I know. but for maximum reliability, I would like a totally manual system, which is why I am saving up for a manual cable system for the front differential. I think I'll leave the Burb alone, as when my wife is driving, I like that she doesn't have to fool with anything, just throw it in 4x4 with a switch. I think it would be too intimidating with levers and things to mess with.
-Rob