i had a peregrine, and if i were to buy another SO i would just get an integrated pack that was bigger than i need.. the x-pac material cleans easily and keeps the blood off of the places that don't. i'm a meat shelf fan, but the SO is the exception to that. i could see their integrated system being great.
you can get big bag for minimal weight penalty, and of all of the pack systems, i think SO is best suited for carrying meat in the bag. i packed out 2 whole bucks and one bull in my peregrine (bought in May) and the first buck i just dropped a contractor bag in as a liner and dropped the meat in there. being a 3500CI bag, it was a little over full, but it worked. of the 3 critters i packed in mine, the inside the bag buck was my favorite.
their meat shelf is fine, and works, it's just not as streamlined as other packs. an integrated frame and big bag seems like the best option to me for SO. if blood does get on stuff, the x-pac is a breeze to clean, and it will not bleed through to the frame material or you... their bags are big enough with no weight penalty that it makes sense with their packs vs competitors.... the gate keeper straps with the internal frame make evening the load and balancing it easy.... easier than most load shelf setups.
like i said, i am a load shelf guy, never considered a pack without one, but if i was running a SO, it would be their internal frame, they changed my mind on meat in the bag