I swear by the Zojirushi stainless steel mug
agree, nice product, but not something I would pack.
I have a Vapur bottle. It leaked the first time I tried it, haven't used it since.
I haven't tried this, but it has a good review: Hydaway 18oz
The Hydaway is an all-silicone bottle with screw-off cap and a spout lid. It does an excellent job of finding the middle ground between collapsibility and leak prevention. Our former pick, the Nomader, is a sturdy bottle—almost like the real thing—but it collapses to not even half its height, about 6 inches. On the other hand, completely flat bottles we’ve looked at, like the Vapur Eclipse, can leak when lateral torsion is applied. The Hydaway manages to scrunch down small, and it passed all of our leak tests.
Laura's suggestion to refill makes a lot of sense.