I have tried a ton of them. My personal favorites are the FHF and Kuiu Pro.
Pros of both:
Sleek, sit high on chest, small footprint, comfortable, quiet, minimalist, modular and not an additional backpack for your front.
Not full coverage. I prefer forward opening lids. Need to purchase additional pads for best comfort.
Kuiu Pro Cons
My Binos fit tight in a large but smaller models won’t and I’m not a huge fan of the slop if I ever switch glass again.
Hard to find and usually sell out of stock instantly.
I am not a fan of carrying much extra gear on my chest. I want bino only, my lens cleaning kit (micro lens pen, Zeiss wipes and a lens cloth) and my outdoorsmans post. Maybe my phone as i use it for gps and camera. That eliminated a lot of my options because the AGC/Badlands etc were enormous in comparison.
I've used a whole host as well. I'm interested in learning more about an upcoming design from Marsupial Gear. I like their low profile design, but I guess they have a full enclosure version coming out.
If you're into hauling a lot of gear, I'd also check out Hill People Gear. They have a bino pack attachment to their chest harness.
While hunting last year the boy took a dive through some snow and after getting up he found his Vortex harness allowed snow to fill the bino case full(I mean FULL) which was a real pain to clean up the wetness from all the snow melting ,etc. Just my .02
I have the Kuiu Pro and like it a lot coming from an Eberlestock Scout model. The Kuiu stays high on your chest fairly well, the straps are so thin they're practically not even there. The side pocket is just large enough for the standard iphone size (not the plus) if you don't have a bulky case on. The front zipper pocket is kind of a joke though, a lens cloth would probably be about the only thing it would be goof for. for 10x42's the large is fairly wide, so there is some slop left and right, but I've gotten over it pretty quickly.
I went to the Muley Freak harness this year from the original kuiu harness. So far, the Muley Freak isn't too bulky, complete closure, quiet, fits my razors well secures high on my chest. The only things I would change are that the pistol holding pocket is a little wonky but not a huge deal and I have to give it the slightest jiggle when closing to get a good seal. Again, not a huge issue. Can't wait to use it summer/fall
I really like my Alps Outdoorz Harness. I like that is has a hook and loop closure, not a magnet. I put my Swaro 10x42 ranges in them and it holds well. They are snug, but still slide in and out easily.
This bino harness costs less than most, but I feel the quality ranks up there. Paired with the rangefinder pocket they are perfect for my archery setup.