They are all safe, as long as you use them in moderation. But most people seem to prefer the sucralose ones in terms of taste, so splenda or one of the supermarket own brand versions of this.
Sucralose is safest with health concerns, as it's just modified sucrose which is normal table sugar. it normally comes in a yellow jar, I use tesco's own brand as it's ALL sucralose (plus an anticaking agent) not a sucralose/aspartame mix.
Unless you have a gluten intolerance it will be perfectly fine, it's a wheat derivative and appears in all the sucrolose sweeteners as far as I can tell - certainly the tecso and and asda ones.