I have the older SLING. I have chest pack, a couple fanny packs, a Hydration Pack all Orvis. The quality is there. I also have three vests. Bad thing with the vest is all the pockets. I forget what is wear. I prefer the sling. I can haul extra reels or spools, 6 System X boxes, and all the extra with builtin Zingers for floatant and clippers and focepts. Mine is the older material, but all else looks pretty similar. You put it over one shoulder and put the strap around your waist and it stays put.
I like it so much I bought a sight unseen William Joseph http://www.flyfishersrepublic.com/re...oseph-equinox/

As nice as the Orvis is, WJ does take it one step farther in my opinion. Mine also has a large patch in the first compartment that makes it double for a chest pack. I will never use anything else.