i use both platypus and camelbak systems, the camelbak being in mine opinion the beter one.
-beter bitible bit valve
-bladder with (almost) no weak spots ( no parts that are folded or will be folded )
-has the ergo hydrolock, the 90 degree turn is great and so is the lock.
-it looks beter ! <img src="images/graemlins/cool.gif" alt="" />

these systems are really great, but bottle's are also here still in service.