So far, DS prefers the Nuby sippy cups. We have 3 of them. I think its the soft spout on them. They don't leak if they are put together properly. I also have a Dr. Browns, which is fabulous and doesn't leak, but, he doesn't get as much from it. Also have an Avent, but, he doesn't like it as much as the Nubys.
Re: Recommend your sippy cups...