Like many, I've owned a few.
Around 2011 I bought an S4, it was my first non-neck strap harness, I wore it half a season. It really didn't offer anything over the neck strap and still made my neck sore as the suspension system didn't relieve the load off my neck/upper back.
Next I had a FHF which was a great harness and I used it for many seasons before my brother bartered me out of it. It is a more open design which allows more access for windblown dirt, snow or rain to enter. Also, the flap that opens upward can be a pain if you wear the harness high on your chest like I prefer to do, I felt like I was always moving my head around to open it up in order to not get slapped in the chin. Limited on storage for certain if that's important to you but I feel it has a great suspension system.
I used the AGC Cub Max for a season. It is a mini pack unto itself, I had it loaded with knives, headlamp, phone, windchecker, licenses, first aid supplies, etc. It got to the point of being ridiculously heavy for a bino harness, it offers far more storage than I need or want. The suspension system is good but if you load it down you're going to want to replace the buckles with auto-locking buckles from Kifaru as they can work themselves loose. The bino pouch does a good job of sealing out the elements.
Finally I now have an Outdoor Vision Ridgetop. I really like it as it opens forward and is fairly minimalistic. It does a good job of sealing out the elements and it has storage for exactly what I want to carry in my bino harness. I do wish the buckles were auto locking but it meets all my other needs. I do carry a compass but I keep it in my pack and the magnets don't otherwise bother me and they're quiet to boot, very little snap when they come in contact with one another.