It's good you didn't buy the GoLite Jam70. I like the pack, but it needs modifications to work. Go Lite doesn't seem to understand how a pack is constructed. They include load lifter straps, but those do nothing but pull the top of the pack closer to your shoulders. Load lifters are supposed to lift the shoulder straps off your shoulders and hang them from the frame which transfers the weight to the hip belt. Properly lifted shoulder straps put 10-20% of the weight on your shoulders and mostly keep the pack from falling backward.
The Jam70 "frame", which is a flimsy sheet of plastic foam, doesn't support all the way through to the load lifters, only up to the shoulder strap attachment. I bent myself a 1/4" aluminum rod to replace the flimsy support panel, but I didn't get it right. See this thread for mine and another's more successful mods: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=64923
What I do like very much is the price, the weight, and the size - my BV500 fits sideways and my quilt and down jacket aren't squeezed into bricks. I really like having the bear can sideways because it doesn't become a pole against your back.
I just got back from a few days on the JMT (Tuolumne Meadows over Donohue to Marie lakes and back) with 38 pounds (don't ask...) in my modified Jam70 and still like it although I will change my frame mods.
I ran across a hapless Jam wearer who had no mods and the pack was collapsed on his back. It looked like an ancient old man hunched over clinging to his back. There was at least a five inch gap between his back and the pack at the worst point. He wasn't too happy with his last second purchase to reduce weight.