Coke Zero is Diet Coke with Splenda instead of NutraSweet. And it does taste MUCH more like regular Coke.
Same thing with Sprite Zero.
Wild Cherry Pepsi, Pepsi One, and Cherry Vanilla Diet Dr. Pepper all use Splenda as well, and all taste fantastic.
I predict the days are numbered for traditional Diet Coke and Diet Pepsi. Splenda is just SO MUCH BETTER.