Ran both. 37" Falkens, and 37" and 40" Nitto Trail Grapplers. I use these on my Jeeps (I have 3).
For an off-road tire, I much prefer the Nitto Trail Grappler to the Falken MT. I also wheel in JV a great deal, and the have never cut a Nitto Sidewall, but have cut a couple of Falkens. I also believe that the Nitto rubber compound and tread design allows for better performance in the rocks.
About the only downfall of the Nittos, is that they are very loud on the pavement compared to the Falkens, and the softer compound will wear faster and can chunk more.