I've wheeled rocks with both MTR's and original BFG MT KM's. Both experienced considerable chunking under my foot which tells me it's the rocks not the tire.
Rockhounds LOVE the MTR's...you can't deny it. They ride hard and make some noise, but if rocks are your game, the sidewall is up to snuff compared to others.
I have KM's now on my Rubicon and hold my breath every time the sidewall rolls over itself. The MTR's were pounded on, lasted 37,000 miles, and I got rid of them well before they were unsafe on wet roads. I'd drive MTR's again if they suited my needs.