Bests & Worsts Reviews from Amazon

I think I've tried almost every straw cup out there, and this one is as close to perfect as possible. When closed, it is almost leakproof. The only times it will leak is when liquid is already leaked into the seams of the lid, in which case the cup will leak, even when closed. We haven't had the fungus problem another reviewer mentioned, but we rinse these cups in warm water immediately after each use. I like that the cup doesn't have handles or a weighted straw. I feel that it is better preparing my son to learn to drink from adult cups. We own six of these, so I guess that shows how much we like them! *** EDIT *** So, after reading two other reviews that mentioned fungus/mold, I decided to crack open one of the lids to check mine. I am usually very paranoid about these types of issues, but I figured that since we were so diligent about rinsing each cup after use, we shouldn't have a problem. Well I was wrong. I opened one lid and was horrified and distressed that there was some funky old slime/guck between the twisting contraption and the base of the lid in a location that is absolutely impossible to access much less clean. It was also still moist in between the twisting part and the base, even though the cover had been washed and was sitting on a drying rack for over 24 hours. It was really difficult for me to crack open the lid, and it is impossible to put back together once you do open it. You basically have to break it open. I'm so very disappointed in these products and angry that I now have to toss six of these cups! That's a lot of $ down the drain because of a clear design flaw.