I have tried lots of packs and will give my opinions of what worked well with them and what I didn't like.
Eberlestock: I had the X2, but have also borrowed a dragonfly. I liked this pack. It was super tough and carried a gun well. However, I found it really hard to remove the gun from the pack quickly or quietly. In addition, both packs squeaked quite a bit when I walked. Honestly they only squeaked when I was covering ground and I take pretty long strides. With shorter strides they were quieter. I also have a long enough torso that the load lifters do nothing for me. This is a handicap for carrying weight, but helps the daypack functionality by making it easier to crawl through brush. Ultimately I couldn't get past the really heavy weight and high cost of these packs and decided there were better choices for the money.
Badlands: I really like the look of the 2200 and Clutch packs. They are heavy but quiet and well constructed. Both of these function better as day packs or overnight packs and won't pack enough weight comfortably for a long bivy hunt. The summit is a nice looking and fitting pack, but I don't trust the plastic stays. If this had aluminum stays it would have been my pack choice. Especially for the price if purchased through the long range hunting store.
Kuiu: I can't comment on the ultra or icon packs, but had an icon pro 1850 that I used this hunting season. First, this pack carries weight really well. I was really impressed with the load carrying capabilities. However, the design of the pack caused it to collect debris and water between the pack frame and bag and this pack made a ton of noise once this happened. Cleaning and drying this area out solved the problem, but where I hunt there are a lot of dead pine trees and the needles built up constantly and I had to clean this area out every couple of hours to keep it quiet. This wouldn't be a problem if I hunted more in open country or wasn't crawling under deadfall constantly. Kuiu customer service was awesome and was willing to work with me. I would still recommend this pack to most hunters. The only other issue I had and it was a minor one was that the pack frame limits your ability to twist with the pack on.
Mountaineering packs: I have used lots of these from Golite, kelty, Gregory, and have checked out Osprey packs, but never owned one. I think for many people a pack from a reputable company in this catagory would be fine for hunting. I am super hard on things though and would rather have something a bit more expensive, but more durable and many packs in this category are built to be ultralight. This is great for hiking trails, but not so great for the type of hunting I do.
Hill People Gear Ute: I don't have this pack yet, but it should be here next week and I will comment more then. HPG makes some of the most durable and well thoughout packs that I have ever seen. The quality is second to none and their designs are simple but effective. I am excited about this pack. The harness system is intuitive and allows a lot of freedom of movement and all the reviews say these carry weight really well. They are also known to pack down to nothing and function well as a daypack. Also the modularity of their system allows these to expand out to be big enough for any backpacking I will do.
Barney's Freighter frame: These are the king of heavy weight pack frames. I have one as well as a super moose bag and am really impressed with this. If you want to carry more than 80 pounds use one of these. In addition, external frames allow the attachment of all kinds of different bags as well as elk or moose quarters. I love this pack, but can't use it where I hunt for day hunting. It is simply to tall and too wide to crawl through the kind of deadfall I have to maneuver through.
Rifle Carry: I have used the kifaru gun bearer this year and love it. I would use this system over any of the slings, scabbards or strap systems I have used. These carry a large rifle comfortably while allowing it to be quick to remove the rifle if you stumble upon an animal when you didn't expect it. In addition, maneuvering through brush and crawling under brush is easy with this system.
Sorry for the long winded response. I hope it was helpful.