I agree with everything that's been said about the Ostrom packs. 

We made the decision to buy, rather than rent packs a few years ago.  I purchased a GG pack (I forget which one).  I'm sure it was a fine pack, but the material didn't seem as heavy duty/durable as what I was used to.  I returned it and called the outfitter that we had used in the past and asked them where they got their packs.  He directed me to Ostrom.  Our group of four now uses an Ostrom for food, a 2nd Ostrom for gear and we use two large sealine's for personal stuff.  We split the costs, knowing that we'll be doing more trips together.

Ostroms are definitely more expensive (eye-opening expensive), but you won't feel cheated once you use them.  I would also add that I had a great experience with Ostrom customer service.  The individual that I spoke with (I think it was the owner?) spent over a half an hour on the phone with me explaining the differences in their packs and how this would apply to my size and trip style.