When I saw this thing in a thrift store, a bunch of thoughts went through my mind. I recalled reading an article indicating that you won't save money on soda this way if you use the CO2 cylinders they want you to use with it. But also that you can buy an adapter to use it with much cheaper paintaball CO2 canisters (which I have ordered as of this writing).
I went and bought a standard CO2 "carbonator" anyway (seen above) just so I could write this review, along with three of their unduly expensive, unhealthy flavor syrups. These contain pretty much all of the nasty stuff normal soda does, so there are no real health benefits.
No biggie, you can also use sno cone flavor syrups which are much cheaper. There's all kinds of work-arounds people who own this device have discovered for making it much cheaper. I've gone with the company's own syrups because again, I wanted to do a fair review of the product as it's intended to be used.
Step one is filling a compatible bottle up to the indicator line. These are allegedly Chinese knockoffs but they're perfectly compatible with the machine, and cost dramatically less. Sodastream official bottles are $25 apiece in stores. I got 4 of the probable knockoffs for $30 right here.
You then attach the bottle using a clever tilt-lock mechanism that saves you the hassle of having to screw it on. This justifies somewhat the existence of this machine, where otherwise a simple adaptor with in-line valve mechanism would suffice for carbonating a bottle of water.
After the bottle is attached, you press down on the top of the unit and wait. You'll hear a rushing sound and see a plume of bubbles inside the bottle. The LED indicators will light up in sequence. You stop pressing down, "say when" style, as soon as there's enough carbonation for your liking (as measured by one, two, or three glowing lights).
Only then do you pour the syrup in. You're urged never to add the syrup prior to carbonating because it gums up the nozzle. Again, I don't recommend buying the "official" flavor syrups as there exist much cheaper alternatives that are just as good. The official ones are mostly just clones of popular name brand sodas.
This one, for example, is "Dr. Pete". Take three guesses what it's based on. The green one above is "Fountain Mist". It's not difficult to figure out. For the most part they taste like existing budget knockoff brands like Shasta or RC.
Here's the result. Three bottles of home made soda. I have four bottles but couldn't bear to buy more than three syrups, being that they were $5 each. The bottles are in the fridge now as I may as well drink my slightly more expensive than usual knockoff sodas ice cold.
Note one appears more full than the rest. It began with the same exact amount of water, I just carbonated it more heavily (all the way up to three lights) to see what difference it made. The volume of the resulting liquid is greater but I don't detect any difference in the degree of fizziness when I drink it. Maybe go easy on the CO2 then and save some $$$.
Do I recommend this thing? Under the following conditions: Find it used for a cheap price, perhaps on Craigslist. Mine was just sitting on a shelf in a thrift store. I wouldn't pay more than $20. Second condition: Buy this adapter so you can hook it up to cheaper CO2 canisters of the type used for paintball. Third, buy sno-cone syrups instead of the official Sodastream ones.
Under those precise conditions, it can be worth it. You won't be saving a huge amount, but it will be somewhat cheaper than store bought soda. The real attraction is the fun of making it yourself. It's a cool kitchen gadget to have which makes something tasty as the end result.
The only really big benefit I can think of is the control it gives you over what goes into your soda. Using the sno-cone syrups instead of the official ones will eliminate many of the problem chemicals like phosphoric acid that make soda so profoundly bad for you.
It'll still be sugary as fuck though, so the diabetes risk remains if you drink soda in excess. Soda is a dessert. It's best thought of as liquied candy rather than a beverage, and certainly not a water alternative. Having said all that I think it'll be a fun novelty, especially when having guests over, and I didn't pay enough to get too broken up about the initial outlay.
If I'd paid the staggering $70 these things typically sell for in stores, brand new, I'd expect much more from it. More than it can deliver. As is, I'm content that it does what I expected and that the cost of the syrups (even the sno-cone ones) will probably ensure, ultimately, that I drink less soda overall.
Stay Cozy!