I use a Liquid Force 2010 Luxury harness find i dont have any trouble with it, i mainly use it when im in the surf. I like how it will swivel on my waist for toe side but does'nt ride up under my arm pits!
I also have a Liquid Force 2010 Comp & dont like to use it when in the surf because it does'nt move a bit, as stated in an above post after alot of boosting i dont think there is a waist harness on the market that won't ride up a bit other than a seat harness. i find when i use my Comp (which is not very often, i like the surfing side of the sport but when its flat i like to have a boosting sesh

) it only rides up a bit but does'nt really bother me. Another good tip is to wet your harness straps before you tension it up, especially when there new, not sure why but it works for me.
Good luck i hope you find what your looking for!!
Give Padi of Surfconnect a call thats where i got mine @ a good price, STOKED! PM me if you want his contact.
Mark