When you figure in all the prices, it comes out to about 50-60 cents per liter. Bart
Not worth it for me, unles my goal was simply to save bottles (which I recycle). Wegman's line of sodas (all diet for me) are 69 cents for 2 liter bottle. From Diet cola, Zero Cola, and a line of diet (zero cal/carb) citrus and grapefruit sodas called "Wedge," diet Ginger Ale (which is actually better than diet Schwepps), diet orange (as good as diet crush), etc.
Also, the selection of diet flavors is limited, right now, for the soda stream. But, I do HATE all the bottles and recycling. So, if soda stream introduces more diet flavors, and makes them readily available in grocery store, or target or bed bath beyond...where ever, I would consider at that time.