I like mine, because it cuts down on having to go back to the store to recycle the empty bottles. (My state charges a refundable fee for recycling on each bottle sold).
I like best to mix the resulting sparkling water with juice (faves would be unsweetened grapefruit or tangerine), and then I add a package of tangerine-flavored EmergenC, which is a powdered vitamin C supplement. I put about 1/3 juice in the glass, add the EmergenC, and then slowly pour in the sparkling water. Yum! The resulting drink is very thirst quenching, and is sugar free, and low-cal. I have not bothered to try out the syrups the company sells, including the free ones that came with the initial kit.
I am not sure if it saves any money compared to buying pop, but at least I can avoid the artificial colors, weird ingredients, and excess sweetener that come with commercial products. I avoid artificial sweeteners like the plague. Most of what I've read says they are much more harmful than regular sugar. I know that artificial sweeteners upset my stomach. If you want to try out a safer low cal sweetener, you might wish to check out stevia, especially the concentrated liquid varieties. Stevia has 0 calories, 0 carbs, and has been used by a native tribe in South America for centuries. It seems safer to me than something cooked up in a chemical lab. About the only disadvantage to stevia is that it has a kind of licorice after-taste to it.
Any way, good luck with the Sodastream.