I recently had the chance to snag several Platypus soft bottles, been wanting one for a little while. I got four 2L and two 1L. These are BPA, BP, and phthalate-free those interested. They are pretty tough tho being soft bottle they can puncture. I like being able to fold them away when finished with the water. I also like having one in my emergency evacuation bag.
I typically I use a camelbak bladder but there are times when I just bring my stainless steel bottle. These are nice to have when I know I can get water at my destination, saving some weight along the way.