When I first discovered the Nuby Straw Sports Cup sipper it was after testing 3 sippy cups and you would have thought I discovered gold. My son absolutely loves this sippy cup but I don't feel the same as him. 

First, the straw part is easily to be chewed by a toddler that is teething so it creates a bigger hole than is intended and this leads to leakage. In my opinion, that defeats the purpose of a sippy cup. I find this to be the biggest drawback of this sippy cup as well as you are unable to purchase a new clear straw insert so you are left with a cup and ring with no viable way to replace...