I just got stuck in the mud last weekend with a 4x4.
I misjudged what I was driving into, had a bed full of firewood, making for about a 9,000 pound truck, and sunk like quicksand into the swampy, muddy mess. The mud was up to about 3/4 of all the tires and there was no getting out of there, 4x4 or not. The difference in my situation was that all four tires spun instead of two.
I was about 30 feet from a paved surfaced and only had a 15-foot tow strap. The guy who originally tried to pull me out with that 15-foot strap had to come off road because of the short strap and started getting stuck himself (in a 4x4 Silverado).
Fortunately, word spread and another guy came along in a 3500 RAM CTD, whipped out his long tow strap, and snatched us out of the muck like it was nothing.
We got back from our camping trip and I immediately bought one of these on Amazon:
http://www.amazon.com/gp/product/B004P9C5H8/ref=oh_aui_detailpage_o04_s01?ie=UTF8&psc=1With all of that said, I will always have a 4x4 truck. They have never failed me in the snow, and I have pulled others out. I now realize, however, why lighter Jeeps with big tires make better true off-road vehicles than heavy pickups with normal tires. :o