After trying numerous brands and styles of sippy cups, I finally purchased the NUK Turtle Active Cup. Immediately my son (12 months old) started using it, refusing to take a bottle any more. I had to purchase 6 more because he loved them so much. It never leaks, is the perfect size, and is very easy to clean. He is now 20 months, and we are still using the same cups I purchased 6 months ago. They are very durable, even against a toddler who loves to throw things. The only thing I would change is the plastic clip that comes with it. We never use it, so I always throw it away. Thanks NUK for a great cup!