I'd say both are equal in quality and value. Our store sells several hundred of each, and warranties for either pack are rare. The new Antidote reservoir from Camelbak is a huge improvement over their previous Omega reservoir. The Osprey reservoir is an evolution of the Nalgene reservoir that's been around for a while. Osprey just tweaked it for improved flow and durability. Both work great.
My one complaint about Osprey packs is their complexity. They're super strappy, have lots of zippers, and widgets. Not very streamlined. To chase the value proposition, they try to add as many features as possible to their packs. In the end, they get a bit overdone. That said, some people love all those additional features.
I would caution against using the Viper series from Osprey. We sent them all back. They went a bit overboard making it stiff, so every one we sold came back with complaints of the pack being too rigid like a turtle shell.
FYI - I'm not the only one who thought Osprey packs were a bit too gadgety. The Euro market asked Osprey for more streamlined packs and those offerings will be available in January.
As for Camelbak, I think as long as you stay in this type of pack, Camelbak makes a great pack. Once you get into packs in the 30+ liter range, Osprey definitely owns that market. We sell a boat load of Camelbak Lobos and Mules.