I use Warm n Natural, even two layers if I intend to use it to put hot dishes on. I think the purpose of most runners is protection from stuff you put on them, so you would want something not puffy, which might be an unstable surface.
I find the format here to be unwieldy, half the time I seem to need to log in, other times not, do not read posts nearly as often as I used to under the "old" format. It seems much more about advertisements than about quilting.