My by far favorite mounting system is the original Robert Beckman (which Bruce Gordon copied) pannier locking system that uses just one or two (depending on front or back) web straps that loop down below a Bruce Gordon rack (has a square bottom) then back up. It uses a cinch buckle to loosen/tighten the strap.and hooks positioned exactly to fit a BG rack. The pannier was extremely secure. I could literally pick the bike up by a pannier. As long as you cinched the web strap (easy to do), it is not going anywhere, regardless of the road surface or condition. I still have several pairs of panniers of his that I need to sell but you need to match them with a BG rack. The only downside to his packs are they were a bit on the small side and not waterproof. Later on, Robert came up with a newer system which I do know much about.
I have tried Beckman, Ortlieb, Kirtland, Arkel, and others but IMO, the Beckman are still the most secure. Unfortunately, I do not think they are made any more.
