Power kites can be really powerful. Respect the power of the wind, especially on gusty winds. Don't try to jump!. A guy took a strong gust, jumped high and land very badly.
Here is the video:

I like using power kites, but I'm always very wary of Jumping...for exactly this reason!

I jump on land regularily! its indeed fun. typically I'm on my speed 3 15m and jumping in moderate winds. I get a nice floaty landing on me big speed.

I've got some friend's that do it here (north of England), and they've asked me to come out with them before. Maybe wait a while before I jump

good advice

You also need to be very careful with your location, avoid any fields with upwind banks of large trees/buildings etc - as you'll need the get a long way away from them to avoid the turbulence they will inevitably cause. Having clear space downwind is equally important!