I tried to give my little girl the traditional kind of sippy cup when she was ready to start drinking water along with nursing. She rarely ever was given a bottle because I was able to personally nurse her at every feeding. So she never really got the concept of having to hold something up in order to get milk. When I gave her the sippy cup she just held on to it and never got the concept that it had to be held up for the stuff to come out.
I had bought a couple straw cups before I bought these and she did great with them. I wanted to get a couple more because I was constantly having to wash the only two I had during the day. My husband actually found these and we decided to try them just for something different.
One feature I really like about these cups is that there is a sliding cover that goes over the exposed straw. It folds the flexible straw down, covers, and locks into place. It keeps the straw clean when we are out. I also flip it over when it's time for my 13 month old to stop drinking. She hasn't figured out how to flip it back yet, so when it's closed she just puts it down.
The thing I don't like about these cups is that the straw does not go far enough down into the cup to get everything out. There is always a good amount left in the bottle that you can't get and end up having to throw out. Also, the way they designed the no-spill feature is a bit hard to clean, but if you take it all apart you can get it good and clean.