I have experience using that rig. It's originally designed for binoculars, but works well for a camera too. Not a jostle-free setup tho. And having to wear the sling was very annoying on a long, hot, hard hike. I won't do it again.

I found Cotton Carrier Strap Shot a few days ago, looks interesting. Strap running to the top of the pack moves the weight to there and in turn to your hips. Makes sense to me.