My mom uses Spelnda. I think it tastes terrible and it doesn't work for cooking. To me, aspartame and Splenda taste exactly the same. It's my personal belief that they're poisonous and they'll kill you, but I can't prove it!
My roomate bought a package of Stevia. She says it tastes fine, but I noticed she's only used it once in the past YEAR since she bought it!