I've tried most of the stevia products. I really enjoy Stevia Extract in the Raw powder in coffee and tea. SweetLeaf Liquid is good too, but I notice even less aftertaste in the powder.

Splenda is OK, but the whole "just a molecule away from sugar" is just marketing hype (salt is "just a molecule away" from explosive, highly reactive sodium, for example). It's a synthetic chemical like any other artificial sweetener.