The two main types of kitesurfing harness: seat and waist. It is also possible to get a seat harness incorporated with board shorts.
Can be better for beginners as they prevent the harness being lifted under your ribs when you fly the kite high while learning
Provide good support while jumping
Provide some impact and abrasion protection for your bottom
Not too good for toeside riding as the harness doesn't rotate and you get a twisting force from the pull of the centre lines.
Harness hook gets in the way if you want to paddle on your board
Can be difficult to fold flat for or packing
More versatile for intermediate and advanced riders. Can be rotated and positioned where you want it
Can ride up under your ribs when jumping or kite is high
No protection for your butt if you impact something with it
Good for toeside riding as you can rotate the harness to adjust the direction of pull
Can rotate the harness book away from your stomach region if you want to paddle a directional board (e.g. during a self-rescue)
Folds flat for travel or packing
Try a harness out before you buy it if you have the option. Some kitesurfing shops may have a rope you can hook onto and lean back to assess the comfort and fit of the harness.
A latch system on the harness is easier to operate than threading straps through buckles, but wash it out in fresh water after every session to avoid rust.
You can attach a harness pouch (pictured above) to the webbing on your harness, and use it to store small items of gear such as a GPS, mobile phone or waterproof money container.