I always had trouble finding a reusable water bottle that doesn't suck. Plastic ones made things taste like plastic and aluminium/steel ones left a metal taste. This one doesn't appear to have this problem, and I'm happy for that.
Not properly made lid. When screwing the lid to tighten it, the thread will not carry enough force and the lid gets loose. The thread should be made more more bolt to withstand more pressure (and not get loose under load).