Rating: 5 / 5
This is provisional as it hasn't been out for more than an overnight and a couple of dry-run day hikes ( one of which was over 20 mi.).
Although this is not the first backpack that uses an independent harness/suspension system with a separate removeable packsack (Dana Designs and the Gearskin come to mind) --this is the most comprehensive iteration of the design and the only one designed for specific dry sack system.
The suspension itself is essentially classic large-pack ULA----slender, removable alum. frame stays which can be custom shaped for one's back, a full padded and ventilated back panel, lightly padded, well curved, wide shoulder straps (using the shape and width to distribute the load rather than thick foam). Load lifters that work ( correct angle can be achieved for most people within it's size range), a sewn in hipbelt (a departure from removeable ULA design)---again, lightly padded (compared to many IF packs on the market), wide, well contoured and closed with 2 buckled straps a la McHale---these allow wonderful fine tuning to accommadate the hip topography of the wearer. The hipbelt also has the classic ULA hipbelt pockets in a larger form capacious enough to swallow a larger digicam, snacks, meds, you name it. Most panel components are made of tough but light Dyneema Gridstop.
How the Drybag mounts and ties into the suspnsion system has been detailed on the Arctic Pack Thread . The dry bags (a 55 and 65 liter sack---made by Pacific Outdoor Equip.--- come with the pack) are a marvel of both lightness and toughness, seal absolutely and make packing very easy----insulated goods can just be tossed inside, no need for separate stuff sacks. Equipment can also be put between the Sack and the rear Beavertail pocket---a good place for wet or soiled clothing as well as snow shovels and the like. The mesh Beavertail Pocket, itself will accommodate a nearly full 2L water bladder. a daisy chain running down the back offers plenty of scope for ice axe or pole attachments.Compression straps are well situated and effective. Do to the nature of the drybag, there are no ports for an inside the pack hydration system. Workarounds are possible---i don't see this as a big deal.
I have found the pack very comfortable with loads up to 30 # so far( I "faked" my loads, loading it up with what came to hand)----it will easily cope with significantly heavier loads----something I hope to put to the test this Winter on an extended ski-packing trip.
There have been concerns about the way the bottoms of the shoulder straps mount into the slots of the Dry Bag----that this is a potential weak point and that if the slots tore, that it would compromise the suspension system. So, far there hasn't been an iota of stress on those slots even with a heavier load. If they did fail---Brian Frankle of ULA has detailed a functional work around to still alow the pack to comfortably work. I can also think of ways to decrease point stress by the strap ends to the slots by laying an additional square (or even 2) of slotted fabric next to the dry bag for the strap end to run through---functionally increasing the strength of the drybag slot.
The only other real lack of the pack would be it's lack of side pockets. I believe the pack was partly designed to cope with bushwacking through dwarf willow thickets on the Arctic 1000 trip by offering a cleaner profile. But, mesh or solid side pockets could be an easy MYOG project---I would suggest that they be designed to slide over the compression straps.
So, to this point, I have no complaints about this pack. It was constructed to a high degree of quality by Brian of ULA to Ryan Jordan's specs. We have the priviledge of not only getting a well designed piece of gear made for one of the more amazing backpack trips of our generation, but one that was tweaked further before it's limited release to the public. These may never be made again. If one were looking for a pack designed to absolutely keep it's contents dry (even to the point of being able to swim with it) and versatile enough to comfortably accommodate loads large and small, I would snag one while they are still available.
Large size weights (inc. frame and dry sack)
41.65 oz. w/ 50L sack
42.45 oz. w/ 65L sack
Essentially a 5 out of 5.
One more thing---it would be nice if a puncture repair kit were provided w/ this pack (not that I've needed it yet!)