Having three kids, we have tried LOTS of different sippy cups, and these remain my favorite. I love that there are no extra parts to clean (that so easily get moldy) and they do a pretty good job of bein spill proof. (Anything will leak when your child shakes it up and down, but these work well under normal use.) I like that they're insulated, especially since we live in Texas where the heat is awful. It keeps water cooler for longer this way.