Oh how I HATE leaking sippy cups-drives me nuts! :) And we have tried them all. The best I have found for no leaks and stoppers that don't fall out when the cup is dropped is the Playtex. They are easy to clean, I take them apart and everything goes in the dishwasher and comes out like new. The Gerber cups have the hard stopper, "leak-proof" thing and if one of the kids dropped it on our tile or hard woods it would pop out of the hole and then the next thing I knew I had drink trails all over the house or car or couch etc. because I didn't know it was leaking. The Avent sippy's would leak if you don't get the lid and the rubber part on just so overall a real pain plus you had 3 seperate lid parts to clean with these. Anyway, sorry for the book but I truly think that Playtex is the best imo. HTH.