Sorry typing mistake. Smooth is a better word. Creamy for me is a nice soft root beer with foam, not too much, and a short but good after-taste. Not a Rooty taste like a Berghoff.
But, A&W has the most vanilla flavoring that I have encountered. It also has a lot of methyl salicylate (wintergreen) which makes the vanilla flavor less distinct.
You can prove this to yourself by adding more vanilla to A&W and barely noticing the difference in taste.
Henry Weinhart root beer has a weaker but more distinct vanilla flavor because the other flavorings are even weaker. You should try it.