They don't suck, they just don't taste like Diet Coke. My kids (who NEVER get real soda) beg me on a daily basis for sips of my SodaStream diet soda. They would drink my entire glass if I let them.

For that matter, if you are dead-set on real Coke, you can buy bag-in-box syrups from your local distributor (or convince a neighborhood restauarant owner to sell one to you) and have real Coke products for less than SodaStream charges -- but you have to be willing to store the larger box and decant from it into something you can keep in your kitchen.