Stays cold (and hot, I presume). Easy to carry, and it fits the outside pocket of backpack. No spills. The auto-lock feature works! And there’s a permanent lock that can be engaged, too if desired. No built-in straw, which suits my preference. Durable exterior finish held up through Iceland without dents or scratches. Thoughtful product design is well executed—even the minimal typography is sensitively handled. Quality product.