The Platypus Big Zip LP (low profile) Reservoir is a burly hydration bladder that is easy to clean and relatively light. Even though it scored the lowest in this review, it did a great job as a general use bladder. It just didn't have nifty adaptations like other bladders tested, and the quality didn't seem as high as others. The zip top closure is intuitive and fast to use, while the quick release system is somewhat compatible with other bladders (and you can change out the mouthpiece).
The new slimmer profile is compatible with many packs but not all. This opening is a little different than a flip top opening, as it seals at the top similar to a ziplock bag instead of flipping over itself. We liked this design, but wished for a larger opening for a few reasons. We also found that in colder weather, the top was harder to peel apart in order to refill. If you're interested in a flip top model instead, check out our Editors' Choice winner, the Geigerrig Hydration Engine. Or if you like screw top options, check out our Best Buy winner, the CamelBak Crux Reservoir.