Here's a link addressing the health question: nutritiondiva.quickanddirtytips.com/is-car
The conclusion from this source:
"To sum up, although soda and other carbonated beverages have been associated with negative effects, carbonation is NOT harmful in and of itself. Drinking carbonated water offers the same benefits as drinking plain water. It keeps you hydrated, which (among other things) helps prevent constipation. Drinking water can reduce your appetite and help you eat less at meals. And depending on the source of the water, it may contain minerals that help strengthen your bones and teeth."
And personally speaking, it was a great way for me to wean myself off of soda in general + get adequate amounts of water intake in a given day! (I loved the COLD fizzy sense in my mouth.)