RE: Isonic vs. jp super-x
For jumping I would recommend the Starboard S-Type instead of the iSonic. As said before, the iSonic is a pure slalom monster, and those boards dislike jumping (of course, it's possible but the risks of damaging your board are a lot higher...). The comparison between the JP Super-X and the Starboard iSonic is also a bit weird I think. It's what we call; 'comparing apples with pears' in Holland. I own the iSonic 111 by the way, and the width and strap settings aren't very good for jumping (but for speed and jibes they are perfect!).
Like Mezza30 said: S-Type