I didn't read all the other answers, but just my .02, yes I do, I changed last year to one.
I no longer carry a pack into a ladder, climber, nor shooting house. Everything I carry fits in the bino harness, my pants pockets/cargo, or hunting jacket.
binos, cleaning cloth, range finder on a pouch attached to harness, phone, charger and cable, extra cartridges, knife, wallet (this is one of those 80's velcro things in a zip lock baggy, it only has a "fiver" and my license very flat, grunt call, rattling bag, protein bar, hand warmers, flashlight, ------ crap, it's been a few months since I hunted deer, what else do I need, I've forgotten what else I may carry? The harness keeps a lot of this for me, no need for a pack up in a ladder/climber.