We bought these sippy cups just by chance.  We had gone out an forgotten to bring our daughters sippy cup.  So we decided to stop by the store and pick up one.  My husband grabbed these ones while I was getting something else.  I was very skeptical that these sippy cups would work.  Just by the look of the cups it looks like there isn't anything to stop it from leaking.  To my surprise it is the exact opposite.  These playtex cups are the best that I have ever used.  I would never buy anything else now.  We never have problems with it spilling and our daughter loves these cups.  She carries...