I agree DTape-- I have a number of frameless packs (G4, Jam, Pinnacle and MLD's Burn) and it really does come down to how one packs them.

I use the Golite's Pinnacle as a winter pack and regularly load it up to 30Lb-32lbs and it handles like a dream-- I wouldn't be surprised if it handled its stated 40lb load.

The Jam on the otherhand is an interesting pack, and it is one that you really need to take care in how to pack it. I very rarely carry more than 20lbs with this pack, however I have been known to strap my hip-waders and attach my wading boots to the pack for some long weekend trips bringing the load to around 26lbs and it carried just fine.

Just to show that these figures are subjective; my wife also has a Jam and finds it uncomfortable at anything over 22lbs. FWIW Glenn-- my wife loves her ACT Lite 60+10 SL for longer trips. She says that it is the most well fitted pack that she has owned and even though it is heavier than the Jam, she still finds herself taking the Deuter 9 times out of 10 for most applications.