I use them and love them!!!
This might be stating the obvious, but do make sure that if you have a lid (personally, I use lids, keeps the water soooo much cleaner) make sure you drill enough or big enough hole(s) to ensure the water does come out easily. Otherwise, you will create a vacuum, and the chickens won't be able to get water, or it will be too hard, and they won't make the effort. Definately would observe them closely to make sure they aren't having to try too hard to get water. I got mine online at Farmtek, I think. Pretty sure I paid more for shipping than the nipples themself!