We used the larger mouth Gator Ade or PowerAde bottles for years, and were very happy with them: Light, cheap, indestructible. Gotta lova that.

But then someone gave me a platypus folding bottle. It wasn't as cheap, but it came with the advantage that we can roll it up as it empties---so it takes up less space, and make fewer sloshing noises when we hike. Even better.

Are they worth the extra dough? We've bought a few at close out prices...