Here is my take on the fountains. Using one for a day or two could be useful. I have one from a yard sale that I haven't used yet but keep it around for an emergency, rehydration or a weekend vacation (mist king could die the day before your vacation and I wouldn't rely on a sitter to do things correctly) After two days I would clean it out with 10% diluted bleach, then rinse the heck out of it, let it dry out completely then put it away. All ways give items like that the smell test to make sure all bleach is gone.
I wouldn't have bought one new because I may never use it and for the money, i could just about buy a cheap back up mister.
I occasionally fill in at a privately owned pet shop. A very good one, where for the most part, they know their stuff. They seldom carry chams but do use a fountain there because it's better than wondering if the chams has been properly watered by whichever of the (approx. 10) opened or closed the reptile room that day. In the case of a pet shop, the risk of bacteria is probably better than the chams being dehydrated.
Ps. I have yet to see my chams drink from the dripper.
