I like the whole concept of this cup. The problem is that every-other-time I use it, there is no suction. I always test the straw before giving it to my son to be sure he'll be able to drink from it. Not sure what I'm doing wrong. Seems like you have to keep the lid slightly loose in order for the suction in the straw to work. And, for obvious reasons, that won't work!
These cups work great for a while. We have owned them for over a year and are still able to use some of them. The straw comes in two parts like most straw cups. The upper part goes through the lid and is very flexible. The lower part extends into the cup and is fairly rigid. The upper flexible straw takes all of the abuse. It is irresistible and your kid is going to chew on it like a rabbit - just like everyone else's kid. You can only get replacement straws for the bottom rigid part. For the price, I expect the flexible straw to last longer or at least the chance to buy replacements for the flexible part too.