Heng C.wrote a review of Platypus Big Zip LP Hydration Bladder on September 24, 2009
The absolute best hydration bladder on the market. I've tried the camelbak, hitec, and outdoor products. I also had the original platypus and this one is a definite improvement with the blue sliding lock. Althought the original one never leaked, I was always skeptical. This one took the question out.
It's also easy to clean.