I'm still trying to find the best combo to keep my pants up, and the FL stretch belt is one of my favorites. I've found it does slip a bit, but overall it does the job well and doesn't get in the way.ha! Completely understand.
I went the suspender route for one backcountry trip and couldn't finish the trip with them on. Where the FL suspenders buckles are is right where my pack was riding and caused a lot of irritation for me. When I am not wearing a pack or doing the daily light weight, easier stuff, the suspenders are nice.
I've tried the FL suspenders, and like a few have mentioned here, while wearing a pack with a waist belt it causes rubbing on the lower back. I still have a scar from those suspenders rubbing my back raw. I have friends who love the suspenders but I still can't figure out how one can tolerate that thick attachment being directly underneath a tight lumbar pad on a pack. How could it ride above or below the waist belt of a pack, considering one is wearing the belt where and how it is meant to be used.