This is for those considering getting the new Jam. I took the new 70L Jam (size large) out for an overnight and here are my impressions compared to the 2009 Pinnacle (also in large):
1. I definitely don't like the new hipbelt sizing and part of the design. Like several others I'm not that fat (32" jeans normally), but the Jam can only go down to ~33" wingtip to wingtip (just under 36" total circumference with the buckles clicked) so I can't snug it as much as I want. The Pinnacle could go at least 2" smaller (I typically had another 1/2" I could shorten if needed). They also changed the way the belt attaches to the pack, I assume to help with ventilation. There may be benefits to the new design there, but it makes the wings more floppy so it's harder to keep from knocking my camera in the pocket when setting the pack down. That wasn't a problem for me with the Pinnacle.
2. I would also measure the torso length to be up to 1" shorter on the Jam. The large Pinnacle was 19" to center of belt while the Jam is close to 18".
The below points pretty much apply to the 50L also, which I got for my wife.
3. Hipbelt pockets seem close to the same size, but zippers are longer on the Jam.
4. Pocket mesh seems like it is not as sturdy - very similar in look and feel but thinner. Hipbelt mesh was also a different kind on the Pinnacle.
5. Sternum strap connection is different. I can't imagine anybody would purposely put that much force on it, but if it does come off somehow I don't see how you'd get it back on again.
6. Top strap on Jam is 7" shorter.
7. Jam has a different cordlock design for the main opening that requires you to use the actual lock and then 2 little straps to open the bag again.
8. The lower compression straps on the Jam cross over a corner of the side pockets thereby reducing their capacity and ease of use.
9. Jam foam framesheet is thinner but stiffer. It seemed to provide as good as support.
10. Shoulder strap foam is thinner, too. That didn't bother me with 24 pounds though the too-large hipbelt was providing me enough support.
Despite some of these "faults" (IMHO), you can't beat the price (especially if you can review a piece of their gear for additional 20% off) so I will likely give the Jam to my son who's wider than me and keep using my Pinnacle. Hopefully they redo the hipbelt sizing and compression strap issue. I'd definitely buy again if those issues were fixed.