After years as a MTB guide, my preference would always be camelbak or platypus valves, with a tap/switch. Bladders are all similar but valves you get what you pay for.
Platypus had an angled one with a valve built in that is really good.
I would check out Camelbak as their stuff is easier to get hold of or check out Opsrey as their stuff is easier.
I have found an angled one easier to use.
I actual found bike bottles easier to use on a bike than a bladder. It made using High 5 tablets easier to use and to play with caffeine ones.
I am trying to work a bladder back into my set up however not as my actual drinking bottle because I found I either drink to much or not enough.
