After using Camelbak's for years and not being happy with how leaky the new Antidote version is, I tried the Platypus. I was happy that it didn't leak under pressure, however getting a good flow of water from the bite valve is a difficult task. Compared to Camelbak's, it's downright difficult. The other issue I find is that it's not nearly as easy to fill in a faucet (pre-hike). This wouldn't be a problem while on the trail, but completely filling it in a faucet is pretty much impossible. I can't speak to the issue about the slide-lock in the other reviews as I haven't put enough miles on it yet (nor doubt I ever will due to bite valve issue). If any of you water reservoir companies need a new design engineer (the 2 mentioned apparently do), I'm available for hire!