After lots of research, I purchased my kids each a Sigg cup and a Klean Kanteen. While I like the LOOK of the Sigg cup better, I am so disappointed with the cup's performance. We haven't had these cups more than a couple of months and all ready there are dents and chipping paint. I know it has this "leach-proof liner," but I wonder how well it works when the cup is dented. My son's cup I can't even give him, as he is only 1 and I worry that he'll bite it and injest some of the chipping paint. I am so shocked that these cups get such great ratings. While I'd definitely buy another Klean Kanteen, I would never, ever buy a Sigg again, especially not for a young child. My daughter is older and more careful with hers, but even hers has a couple of spots where the paint is starting to wear. She does love her cup, a 20oz Sigg and will be so disappointed when I wind up tossing it. Sigg cups are so expensive. I expected that it would last for years, not merely a couple of months.