I still have the almost first version, which was a black neoprene tube with skinny straps. It held a 70oz bladder, no fancy 90 deg. turned bite valve. It worked very, very well when I was road riding in the summers in the deserts of New Mexico. It was pretty much the only way to carry enough liquid and keep it cool, which it did even in the hot sun.

I'll still use it on road rides if I don't expect to be stopping for liquids, otherwise can get by with 32 and 24 oz bottles and plan to stop.

I never found it too hot or burdensome and did find myself drinking more often then with a bottle. A bit easier to keep clean as well.

Then of course, it tells all the roadies in their Euro Pro racing gear that I'm a mt. biker !.