I've tried several of the numerous harnesses on the market; can't stand any of 'em. They are slow to get into or out of, they plaster your clothes down against your body and are generally uncomfortable. Frankly, they're a PITA; a marketing solution to a non-existent problem.
Yes, a binoc hung on a strap around your neck doesn't work too well. Bounces around, swings and sways, and is generally unsuitable for almost any level of physical activity. But adjust the strap long enough so that you can place it over one shoulder, with the binoc hanging on the opposite side against your ribs just above your belt, and you are set. For walking, the binocular hangs there on your side, protected by your arm and completely out of the way. To use it, just grab it and slide it forward and up to your eye. You can let it hang there in front of your chest if you like, making it even more instantly available for use. If you're climbing or crawling, you can slide it around behind your hip, which affords it even more protection. Getting into or out of this rig is lightning fast so it's easy to quickly add, subtract or adjust clothing layers throughout the day as required.
I like this system best when it's used with a very narrow leather strap; no buckles or other gadgets to complicate things.