Binocular neck strap vs harness? And can all binos adapt to a harness?

I'm thinking of getting myself/asking for a binocular harness this Christmas! Does anyone have any opinions on neck strap vs. harness? Is it a nice upgrade?

As a related note, can most/any binoculars be adapted for a harness? Or are they more specific? I'm also thinking of getting new binos within the next year or so and I wouldn't want to buy a harness that wouldn't fit another set of binos.

TIA!