PRM, arcteryx, like most of the pack makers, have given into the obsession of grams over comfort and have trended to lighter packs. Lighter packs are good to a point, but most just don't carry truly heavy weight like a pack with a bomber, adjustable suspension. Adjustability is paramount in an internal. That genuinely means they need to come in multiple sizes. One-size-fits-all, generally means about half or more aren't fit by it.
Get your torso measured and start looking for a Bora 80. It's about the most comfortable hauling pack I've ever used. Beefy, shapable aluminum stays, and the brilliant "outrigger stays" pioneered by Dana. No internal used for carrying truly heavy loads should be without those IMO.
The state of packs today is depressing. You can find light, but it's difficult to find comfortable. I've been trying at least one, new. light pack every year for backpacking, and I haven't found one yet as comfortable as my heavier packs.
I'm not going to quit just yet, and will likely try a ULA Catalyst, and the new Exped Thunder 70 for this year's summer backpacking, but they'll not be going hunting come fall. I'll either use my Bora 80 or Crescent 75.
