I use a 3 litre camelbak OD Cordura hydration pack in my AUSCAM Cordura South African M83 webbing. The entire 3 litre rig which has a backpack of its own fits just right in the detachabe M83 pack on the back.
I have had it for sometime time now, and it has endured some hardcore Australian conditions from below freezing of the southern Alps to over 50C, in the dusty outback or the humid 35C tropical jungles, where everything seems to get some type of rot. Its been bounced around in UNIMOGs, Land rovers, APCs, C130J's and helos. Its been squashed, stepped on, used as a pillow, and not as much as a drop of leakage.
Personally I would stick to the brand, as I believe that anything else is inferior. When working with the British Royal Marines last year, many haad the same thing in DPM with an NSN, and fresh from Basra, these guys loved the system. It worked well for them.
I carry a canteen cup in my ruck.
My 2c.
Cheers,
Wes