I use ARM ballast, rock, and dirt almost exclusively, as it is closer to scale than the others. I model an early 50’s shortline, and it did not use ballast that was 6″ in diameter — where they used ballast at all, nor were roads covered with 3″ gravel as a driving surface.
The products are very rock-like – – since they are rock. I coat my sandstone rock surfaces with fine rock powder, then weather it. Looks just like rock — again, since that is what it is.
I love the stuff, as you can tell.