yea, fuckin searchbar for shit this obvious.
and, cause im bored, ill answer your dumb thread anyway:
lifters increase the torque on your edges, as well as increasing the possible lean angle you can achieve in a turn. because of all this, maneuverability is replacing stability. stability and control is key for park riding, so lifters are bad.
i have ridden skis mounted exactly the same with lifted and non lifted, and, on the ground, and for jibbing, its not particularly noticable. However, landing jumps, ESPECIALLY when your landing switch or catchin a big spin, lifters suck ass. its really easy to catch an edge and for the ski to cut out, resulting in you flipping dh and eating shit.
For wide, all mountain type skis, not a bad idea, specially if theyll be used on groomers. leave um off for pow.