I believe ADA Aquasoil just lowers the pH, instead of buffering it. Buffering implies that any tank with Aquasoil would have nearly the same pH, whatever else was in the water. I'm not at all sure I am right about that though.
Any inert substrate, unless it also has a reasonably good CEC, is as good as any other, other than how it looks. I used to be convinced that black blasting grit was harmful to cory cats, but I recently learned that I was wrong about that, so it is just a different looking inert substrate. Now, Zeolite sand should be a lot better, because it does have a genuinely high CEC. It is ugly, but should be good for plants. (When I tried it, it didn't seem to be any better than pool filter sand, as far as the plants were concerned.)