I've been searching for the perfect lightweight pack and have gone thru a bunch. I started with Eberlestock; J107, GunRunner, X2. They're well made as noted above…but poorly designed for load. Under moderate loads (45 lbs), the hip belt starts slipping. At 60lbs, I felt like my shoulders were bearing the whole load.
I have 3 Mystery Ranch packs; NICE, Pintler
Pop-up (I keep getting sucked in to buying to find they haven't changed their suspension philosophy). They carry weight well. They won't be the lightest pack and their suspensions are overbuilt…but they do ride well.
I've killed a 1st Gen Kuiu. Shoulder straps blew up. It was light, hauled reasonably well,
…but the light weight comes at a price. The nice lady in Customer Service said the packs were designed to last a guide a season. I believe them. They replaced the pack.
My favorite is the Seek Outside. I've been rocking an Evolution with a talon for about 10 years . I think it weighs around 2lbs. It compresses down to fit on an airliner overhead, and carries loads the best of any pack I've humped. Something about their hip belt design/materials. It's carried dozens of animals across probably hundreds of miles of hunting and training. I liked it enough that I got my son one…(so he can pack game for his dad now).
I've got two Kifaru's. The hauler is ok. I also have a bikini frame with different bags. It handles loads ok. Lots of flex and wobble as the weight gets north of 60lbs. The kifaru internal frame packs don't interest me. Too heavy.
If Seek Outside closed up and stopped making packs, I'd try a Stone Glacier next…maybe an exo after that.
I've probably got another 6 packs like a Dana Design, a Badlands (no bueno) and a USMC ILBE (good but heavy).
…ask away if you have specific questions about any of the above.