I've ridden with one, and noticed quite a difference (same model bike). Nothing that hits you in the face, you just end up feeling like "Gee, the last time I rode that trail I didn't feel NEARLY as confident. Huh." REALLY makes a difference in the rocks or in deep sand. Same effect no matter the motor size, Matt.
That said, the budget has not to date allowed for one.
 I did put a decent damper on the Duc, gotten used (Ohlins unit from a wrecked Duc). It does indeed change the way the bike feels, and when I turn it to zero effect, the bike just doesn't feel as confidence-inspiring. That is on a street bike, too.
Heb Dduw, heb ddim; Duw a digon
I'm that gun-totin', farm-raised, evangelical, pro-environment, OHV ridin'/drivin', Southern civil rights pro-labor Liberal yo' momma told you couldn't possibly exist.