As in all things human, one man's trash is another man's treasure. In the long run, it will come down to what you hunt, how you hunt, where you hunt, what you like, and what feels best for how you're built.
In 36 years of hunting, I've gone through more than a few packs - including military surplus packs from WWII and Viet Nam. I've used several of the brands mentioned in other posts but have, finally (thank the Good Lord), found two that work best for me.
One of my problems has always been fit and comfort. I'm 5'8" and weigh about 180. Short body and stocky. I hunt in Eastern Washington and prefer open land (see picture at left) to cover. Ridges and draws rather than tight spaces and trees. I prefer hiking, glassing, and stalking to finding a "sweet spot" and waiting (I don't have the patience). So the choice in packs for me has always been light weight, tough, organizable, hydration fitted, strong warranty, adjustability, comfort while carrying, and room (1800 - 2200 cu in.). If I need to pack it out, I carry a plastic drag sled and stay within radio range of my partners. We've never had a problem even with a 300 pound black bear.
The two packs I finally settled on are the Badlands Monster Fanny if I'm only going out for morning and afternoon hunts and the Tenzing 2220 if it's going to be an all day affair (spotting scope, small tripod, food, 2 liter bladder, sled, and everything else needed).
Both work best for ME, my body shape, and the way I hunt even though I know there are many great brands and types that others swear by...because they've found what works best for them. And that, in every piece of gear you will ever use, is the bottom line. It has to work for you because you are the one who has to use it. Stick with products that carry long and simply stated warranties, see if you can borrow different types of packs from friends to try them out, and ALWAYS remember the old saying that "you can either buy nice or buy twice" and you won't go far wrong.
There are a lot of great choices and brands out there. You'll find the one that works best for you. Just don't be afraid to change if you're not satisfied with what you have.
Larry S.