BULL SH*T!!!

Out of the box is when its the best contneder.

A stock 4x4 Xterra can keep up with just about any other reasonalbly priced 4x4 out there.
Large trucks have a few advantages but are too big, Toyota Tacoma's are a bit more capable but are expensive, Jeeps are a little better but are very closely matched when still stock.

Petersen's 4W&OR did a review on a few SUV's and trucks and one thing I found interesting was that the Xterra's minimum ground clearance was ~.5" above a Chevy Avalanche, 1" above the Jeep Grand Cherokee and 2" inches above the Jeep Liberty!
The only vehicle that rode higher was a Dodge Ram by .25 inches!

I haven't seen a picture of a stock Grand Cherokee on anything that a stock Xterra couldn't do (I'm sure there's one out there but I bet they took more damage than to make it worth it).