I have hunted with the Pintler pack with Guide Lite MT frame for the past few years, packed a couple elk and deer out with it, and recently picked up the Sawtooth 45 on the Mysterium Frame. For me there were a couple of pros and cons of the new design:
Pros - Didn't squeak like my Guide Lite MT was doing at the end
Under minimal load (30 lbs or so of daily hunting gear) the new padding was very comfortable and breathed well in 60 degree weather
The new meat shelf load straps attached to the frame did awesome holding my load securely and coming down steep side hills I never had my meat shift or need readjustment (1 load of two front quarters, the second load one hind quarter and the head)
Storage was sufficient, I easily organize my kill kit, first aid kit, and other necessities with the internal pockets, Upper storage lid seems a little smaller but not horrible compared to the pintler. You do have to unzip your pack all the way down to get to stuff in the bottom which was a little trickier when loaded out with meat
Load lifters worked great for putting more of the load on my shoulders like the Guide lite MT frame did
The new material on the face of the pack seems like it will do a good job of being water repellant, its super easy to clean up when covered in blood which was nice
Cons- Under load with two front quarters the mysterium shoulder padding seemed to squish down pretty good which seemed less supportive than the guide lite mt padding under load
The velcro used to adjust the pack position for your torso length didn't hold tight and shifted a few times, where I could see on the level indicator it being down lower or sideways which made for an uncomfortable pack out at times
Overall its still a good pack, it was comfortable to hunt all day in and did a pretty good job on pack outs. Hope that helps someone else interested in the newer frame.
