Not sure what the big deal is with this new water bottle that unscrews at both ends. They're talking about issues with mold, but I've never seen that on mine. After the ride, I wash out the bottles, and hang them upside down on a wood rack, and they're as good as new. My frustration is dealing with keeping the nipples (especially with the Camelback) clean. If anyone has suggestions for those, I'd love to hear it?