The Horticultural Grit is sharp edged and does look much more prototypical, but as I mentioned, the last delivery of gravel was the wrong size.I have better stability problems with the sharper edged gravel, as the prototype railroads use. Yours looks a bit too rounded for my taste, I like the look, but the smoother edged stuff did not lock the track in place as well as the sharper edged stuff, again just as in the prototype. (I had the local home goods store change suppliers and found this out by direct experience).
I do see that your track "base" is pretty level, so I would wager you are not affected much if at all. My roadbed is elevated, and the inherent movement has the ballast "work away" off to the sides.