We went through several different brands of sippy cups while trying to find the one's that work best for our son. Nuby 9oz Insulated No Spill Straw Cups are the best we have used. They have great designs on them that make my son want to use them. They are the perfect size, making it easy and fun for him to use. If you clean them when you get done using them they are easy to keep clean. I do understand what someone else said about cleaning the straws and mold, but only because of my own fault. We somehow "lost" a cup of milk in the car, and didn't relize for several days later. Talk about gross,...