Here's how I look at it. If I were only going to have one ski, it would be the Karma. It skis, for lack of a better term, like a GS race ski that can go backwards and jump. The PE is close, but not quite there. I have 2 skis (park & 'carving') so I have Foils for park and either a Head Monster 82 or Elan Magfire 12 to carve on.
If you are a strong skier (maybe used to race) the Karma rocks. If you are more of an intermediate, I would go with the PE. It is a little softer and more forgiving than the Karma.
--rick