Well, it's not actually a sentence at all, but a sentence fragment (with a misspelled word, it should be “More comfortable for you all!”). If you want to make it into a sentence it'd be something like "It's more comfortable for you all!" but if it's not part of a lot of text, then it doesn't necessarily have to be a sentence and you should just correct "comfortable."
That makes it a correct English sentence, but in my opinion it still doesn't make a whole lot of sense as an advertisement. More comfortable than what? Than it used to be? How? Or is it more comfortable than the leading brand? Maybe it makes more sense in context, though, and it's just my opinion, so you don't have to pay attention to it.