Many people with a LOT of backpack hunting experience consider Kifaru and Stone Glacier packs to be the best hunting packs available.
Kuiu is another pack that gets some very good reviews, especially from their later versions. It is my understanding that Kuiu is a new player in the hunting pack game.
These 3 are light weight (SG is lightest weight) and can haul heavy loads as per reviews on various forums, I personally have no experience with any of these.
These 3 packs will cost $550-$750+, depending on accessories and custom modifications. Each one will have its own advantages.
Just remember, everyone has their own favorite pack and will have valid reasons why they think it is best. I sort of compare it to the "best rifle caliber discussion", there is no right or wrong answer, you have to find what works best for your application within a given price range.
Hopefully some of the guys on this forum that have a lot of experience with packs and back pack hunting will give some input.
Good Luck on your research