I rejected the Flash because I have the daypack version, and watch people suffer with it when they load it with gear. I don't think the suspension matches the volume of the pack - way too easy to overload it.

I'd look at the ULA packs, and possibly Granite Gear - I have a Nimbus Ozone and use it for heavy trips, up to 40 lbs, comfortably. I would take it if I needed the largest bear canister. The Nimbus series are adjustable and the belt/harness are swappable, so they work well for folks who need a little customization.