Just to be clear i'm talking about the "Purist" bottles made by Specialized the company which use a proprietary coating that seems to work well, not bike bottles in general. See for example [this review](http://www.cyclingnews.com/features/product-review-specializ...). I only recently discovered the bottles so can't give a long term review, the manufacture does recommend against scrubbing them.

Uncoated stainless and glass are great options as well but not practical for some uses.