For those of us who prefer the Innova shoulder/straps bags like the Discarrier, Tournament, Deluxe - the Infinite Discs Tournament Bag at $ 30 ain't a bad substitute.
In the same way Innova uses Infinite as a channel for discs, Infinite is the only channel I know of for those bags.
While the Innova bags were of very high quality, the Infinite Discs Tournament Bag is about 90% as good from a quality perspective, but at $ 30+shipping, I am pretty happy, I even bought a backup on Black Friday last year because they were discounted down to $ 23.
I think backpack bags tend to tighten/tire your back over the course of a round, which is not good, a tight or tired back impacts throwing and putting.
High-end hiking/backpacking bags always have waist straps that put the weight of the bag on your hips, not your back, but disc golf backpack bag manufacturers have not tuned in on this yet.