I tried Grippers once last year and put the Powder Pro's back on after the 1st day, just couldn't keep it on the snow and the trail performance wasn't quite as "confident" as the Grippers. A guy I talked to today said he went from Grippers to Gen III's and said it was a HUGE improvement, to the point he bought another set, his sled would drop a ski whenever trying to turn in powder so bad he was about ready to sell the sled but the ski's made all the difference in the world.
Must be a lot to the setup that each of us use also....