Make your own Sodas?

So I listen to the Dan Patrick Show at work and he’s been pushing this product called SodaStream where you can make your own soda.  Have any of you guys heard of this?  Anyone used it?  If this thing really works I would really change the 2 liter bottle game at the Smith house.  It doesn’t say anything about recharging store bought drinks on the website, that I’ve found, but just wondering everyone’s thoughts and reviews?