Dr. Mercola says it perfectly:
"It’s very important to realize that Splenda (sucralose) is actually NOT sugar, despite its marketing slogan 'Made from sugar, so it tastes like sugar.' Rather it’s a chlorinated artificial sweetener in line with aspartame and saccharin, and with detrimental health effects to match."
I've been using Stevia as a calorie free sweetener for years. I use Stevia in my tea, coffee, and smoothies. The protein powder that I use for my smoothies does not have sugar, so I use a bit of Stevia extract to sweeten the natural sugars in the fruit.
Stevia is a natural sweetener made from a plant extract. Splenda is not sugar! It's loaded with chemicals that actually remove healthy bacteria from your body! And the article mentions something that is commonly attributed to high-fructose corn syrup (HFCS), the dangerous result that your body loses it's efficiency to regulate your blood sugar naturally.