Only had a few trips with it so far, but in sand, gravel and mud have had no issues. It's easily accommodates the 5 of us plus our taller than average greyhound.
Got off road a couple of times in VT and Quebec and had no issues with approach or departure. Granted, these weren't hardcore trails, but it's all in what you'll be using it for. We use it for heavily rutted beach sand trails, forest service/fire roads and mild to moderate trails. The Geolandar AT/S have been excellent so far with respect to ride comfort, road noise and traction.
The National Luna PPP has worked great and is a semi-permanent feature in the back of the truck. Planning to add a police style push bar up front for lights, a 2" lift (new torsion keys and spacers), and if finances will allow in 2010, a Warn Hidden Winch mount.
Ride comfort is far superior to the solid axle leaf sprung front end of the Excursion but comes with the inherent limitations of IFS on suspension travel.
Final plus for us over the LC100 was the ability to run in 2WD most of the time and save a few mpg. :smiley_drive: