I have a couple of these. They work well and yup, you have to keep them clean to prevent bacteria buildup! Also, the motors (pumps) on these do not last long!
I have one that I can't use the pump is too loud or the vibration terrifies my cham she went nuts trying to get out tryed looking for a new quiet pump that would work with this to no avail. If any one can point me to a new pump I'd like to try it again.
Knowing that one of the greatest reasons people leave chameleon husbandry is the time that it takes, I would recommend that any cantina or fountain not be used. Not having the time, or forgetting to clean it weekly (or more often) will possibly give your chameleon access to contaminated water.