First one I had was a Platypus which was ok but not as good as the Camelbaks I've had since. Better bite valve, push fit hose and wide fill neck. US army use them I think.
Only place I've seen mould in the Camel was in the bite valve which turned black and was nigh impossible to clean out.
Maintenance is periodic soak with Steradent tablet. No side effects yet....!
Great forum, loads of good reading...