I've been using and abusing my Kifaru for years and years in Western US plus Alaska. An amazing pack plus frame capable of 100+ loads. You can also customize them to your desired needs with pouches, lids, accessories, and bags. I actually have 2 different bags that I can trade in a matter of minutes. I use one for extended hunts like Alaska sheep or other backpack hunts packing out elk sized game plus capes, etc. I also use it for turkey hunting for hauling decoys plus a tom or 2 out! The padded belt, shoulder straps and padding on the back are pretty tough to beat with Kifaru. Also they design pack frames for your particular body frame....with gobs of adjustments.
The top packs available tend to be Kifaru or Stone Glacier. I picked Kifaru because it had more accessory and bag options plus it is camo. If you want the best I would highly recommend either of those 2 brands. Some Alaska guys tend to like Barney's which would also be an option. The thing I didn't like about Mystery Ranch is the darn weight of the pack plus frame. Kuiu just wasn't designed for 100+ lb loads.
If you are tight on $ I would recommend finding a nearly new Kifaru frame/bags/accessories on Rokslide, craigslist, marketplace, etc. I bought to nearly new frames and bags for about 1/2 price.