Title: LEAKS unless you hold it completely upright at all times.
Review: It is not leak proof. It leaks, by design, unless you hold it 100% upright at all times. Heck, normal glass without a lid is as good as this. DO NOT PURCHASE IF YOU WANT A TRAVEL MUG. Otherwise, good as an expensive stand alone mug which kinda keeps your drink warm (when it's not spilling all over you).
Is this product review negative?