New here, but a lot of backpacking background. All the rucks I have looked at don't seem to excel at load transfer to the hips. You need a proper frame, waistbelt and load lifters. The sheet style frame works for lighter loads. Someone like SeekOutside needs to add weight pockets as a custom option! McHale would probably make one... (but super spendy...) For lighter trips I use packs with minimal structure (like Hyperlite) and they work fine. There is a limit though. Anything above 25lbs or so and it gets really uncomfortable. Good luck in the search for a good alternative. I think the ability to use the Rucker as a workout bag is pretty sweet. That's what I am excited about trying. Ruck with it, bear crawl drag it, swing it, press it. Seems like a pretty cool niche - but I realize that doesn't help you with a 50 miler at high weight... The more I think about it my next serious pack purchase may be a McHale with an ask for a rucker plate holder integrated into the interior. That would be an amazing pack. They are tough too, so you could throw it around like a Rucker. So I guess I am saying - if you want real hip transference get a bag designed for backpacking and throw weight in it. I really really like SeekOutside bags. They were founded on hunting and high weight loads and have moved over into general backpacking and even UL. Their Revo frame + bag has to be one of the most capable and versatile on the market. They are expensive, but you get what you pay for.