Used two as my only bottles for 211 miles on the JMT this summer. Overall great bottles, easy to drink out of and easy to store rolled up in a pack or pant pocket.I did however manage to break one near the end of the trip. I dropped a full bottle from chest height with the cap on and the plastic split alone the seam up near the neck. The split was about a centimeter long, and while I put tape over the hole, the nature of the flexible bottle meant that it would constantly be under pressure while in a pocket and would force some water through the tape. Arguable this was a fluke, as I've dropped them many times and this was the only problem I've had with one breaking.The only major disadvantage to this bottle is that they can't be filled from a pool or river of water. They can't hold their shape underwater so they only get about half full. They either need to be held under a water fall, or be filled from another container to fill up all the way.
Used this for a 4-5 day backpacking trip in 8000-10000 feet elevation at Red Mountain Basin in John Muir Wilderness. Fits well on the side pocket of my Osprey Exos 58. Mainly for drinking while hiking. I had one of these + 1L smart water + 2L Platy. 4L total capacity was plenty for our trip. Light weight, great capacity, clean taste, collapsible, durable, impact resistant. I like the closure cap, not a huge fan of the push pull or hyper flow. Push pull and hyper flow caps are just harder to clean compared to the simplicity of the closure cap. Only problem is hard to fill in lake or stream. I used a rigid smart water bottle to fill up in lake or stream and pour into this 1L platy. Any rigid water bottle/Gatorade would work. One more small complaint is that is takes a long time to dry at home with the cap off. Takes like 3 days to dry. Not a big deal. I still love this water bottle and will be my go to for backpacking.
Now that I have one, I'm surprised everyone doesn't own at least one Platypus. Even if you don't anticipate getting thirsty, it's so easy to stick a few ounces of water in your pocket, pocketbook, fanny pack, even an evening purse just in case the need arises! Never be caught thirsty again! The Platypus is very sturdy, but extremely flexible and lightweight. You can fill it all the way, or just take a little water and roll the rest of the bottle out of the way. Also stands well on its own whether full or with just a few ounces of water.