I was considering both of these packs. At the time of purchase Backcountry was out of the appropriate sized Kamber, so I had no choice for my splitboarding trip that weekend. I used the latest version of the Gregory Targhee 45 for two days while splitboarding and doing some avalanche training. Here are some compare/contrast observations that I made.
HELMET CARRY: system works well and easily stowed; faster to use and stow helmet than Kamber 42 system as it has a zippered pouch where it stows and remains attached to the pack. The Kamber has four attachment points, but has to be completely removed to stow away completely. I can see this piece getting lost easily for this reason. However, the Kamber allows you to carry your helmet on the back or top of pack. Might not be a big deal, but I could easily stow and remove using gloves on the Targhee, but it is challenging with bare hands on the Kamber because of the little clips/hooks they used. Def try this when checking-out the packs.
POCKETS: The Targhee has them, but the Kamber has a few more; specifically mesh pockets on the interior of the avy compartment and the main storage compartment. Most importantly for me, the Kamber has a hipbelt pocket on both sides, where as the Targhee has a pocket on the right hip and a climbing harness style gear loop on the left side. I'd rather have another pocket for splitboarding. The lid on the Targhee is one compartment vs two compartments on the Kamber; one for goggles and the main lid compartment. I prefer the two pocket design on the Kamber.
COMPARTMENTS: Targhee backpanel access is separated from the shoulder harness; Kamber harness is part of the back panel. I noticed this because when I use a hydration bladder on the Targhee, the hose is routed through the main portion of the pack, so it gets in the way of accessing the main compartment as you can see in the pic. It's not a big deal, but makes is slightly more difficult to access or load gear via the backpanel. Avy compartment is slightly narrower on the Targhee. The entire profile of the Targhee is slimmer vs the wider Kamber 42. I find the top loading access slightly easier to manage on the Targhee as the Kamber has an extra flap that is used when the lid is removed; not really a feature that I would utilize, but may be worth the extra hassle for those who would use the lid as a daypack and want the extra assurance the main pack remains covered. The Targhee definitely packs down nicely when not full. From what I could tell the Kamber did as well, but again that was an in-store eval only.
SUSPENSION: Both packs felt solid here; Targhee is offered in 3 torso sizes so you may be able to get a more specific fit. Again, note the backpanel/shoulder harness is one piece on the Kamber.
SNOWBOARD CARRY: Both offer similar ski carry options, but the Targhee does vertical board carry only, where as the Kamber allows for horizontal or vertical carry. I did notice that the upper straps for snowboard carry on the Targhee are not reinforced as the lower straps are. The Kamber has the same reinforcing material on upper and lower straps.
CONCLUSION: I'm content with the Targhee for now, but I'd like to try a Kamber for a weekend to see which one is the better choice for my application. The Kamber observations were made in-store both before and after I spent the weekend with the Targhee.