I've worn it both ways, but historically preferred the harness under the PDF, mainly because then the shoulder straps are tight on my shoulders.
Now I have a fancy pants Zhik T3 with the safety emergency detach/eject velcro. Fits nice, in particular since my wallet is now considerably thinner 🙂 –
Anyway, if I ever need it, the eject velcro won't do me much help if the harness is under the PDF, because I can't easily detach the shoulder straps nor get out of them. So _over_ is the safe option. But now the shoulder straps "fall off" my shoulders anytime they're not under tension.
Thoughts?
I have a Magic Marine harness and I think on my quick release, it lets go of the spreader bar in an emergency and wouldn't require removing the shoulder straps. I could be wrong though... My harness fits best UNDER my PFD and the emergency release is still below the bottom of my PFD.
I wear mine under