The new OR harness is both. It's a waist harness with removable leg straps. I have been riding it a bit lower than my regular waist harness, with the leg straps on. It feels like a waist harness, but can be worn lower, never rides up and the straps take some of the load on big jumps like a seat harness. The straps also come off (i'll remove them in waves) and it's a solid regular waist harness.
I'm biased towards OR gear, but I wouldn't ride in a uncomfortable harness just to ride OR. This one fits well and is well made.
And a bonus for the fashion conscious kiter – the leg straps can go under your board shorts and it looks just like a regular waist harness.
check it out