Generally speaking, I'm not a big fan of drop-leg (thigh) holsters, tho find them preferable when hiking or camping. We can't OC here in Arkansas, so it's not yet been something I've done much of, tho did in Virginia almost two years ago during a family vacation. They definitely have their uses and I prefer them if I'm wearing something other than a pair of dress pants, khakis or the like. They're great if you're driving, as well. Wore them while Deployed during my AD USAF time, as well as a part of my job running an armory and find they work well w/ABU's and like pants.
When I do wear a drop-leg, I tend to wear it as high up on my thigh as I can, almost uncomfortably so - if you guys know what I mean. I don't like it down too low, as it tends to flop around a bit too much.