I purchased a black one when they were on sale a few months back with the intention of using it as a travel pack (hence the black color). Because of COVID19 I haven't used it much other than one road trip with the family and it mostly just held clothing for a weekend.
Recently, however, I've been looking to re-purpose it to a PRS bag. It has approximately 25lbs worth of stuff in it (rear rifle bag minifortune cookie, pouches with range finder and kestrel, few boxes of ammo, tool kits, tripod/head, rain jacket, etc). I don't have a lot of experience with HPG packs, only their chest kits. I have to say the harness on it is one of the most comfortable I've ever used; way more comfortable than anything from Kifaru or MR. For reference, I have a shapecharge, 26" duplex, MR Nice with crewcab, Urban Zippy, and a ton of various other bags from mountain hardware to kelty and osprey. As far as cons go, I don't like that the mesh pocket on the inside of the front flap has no closure (velcro or otherwise) and I find that the hypalon panel on the front makes the pack kind of "strappy". There's straps and attachment points everywhere!
I hope to get more experience with it in the next few months, so I'll try and update this post in the future.