We looked at the Soda Stream. We ended up choosing the
ISI Twist n Sparkle instead for a variety of reasons.
First, we wouldn't be locked into a proprietary CO2 cartridge. The twist just uses 8 gram CO2 seltzer chargers that can be bought at a variety of locations (I found the
best buy on ebay) which are also directly recyclable. You don't have to buy their 'sparklets' which are more expensive (or at least not any cheaper) than any other 8 gram CO2 charger.
Second, it doesn't take up any counter space. We just have to store the bottles when not in use and the wand fits in a drawer.
Third, it's portable! It's fun to take with you and make drinks for others.
Fourth, it was less expensive both upfront and long term.
We don't use any pre-mixed syrups. We use crystal light, torani syrups, Mio and alcoholic beverages in ours. We have a blast using it and I'm very happy we purchased it!