I ran the Toyo Open Country M/T for years on my daily. It is a great tire for heavy off roading.
We actually ran the DOT Tires racing in SCORE / CODE / & Record off road desert racing down in Baja California with great success.
That being said, when I needed a new set for the daily, I went and purchased a set of R/T Tires. I am much happier with the daily driver now and the tire's street characteristics compared to the M/T.
Overall, it is much quieter, and a smoother rolling tire. I dont get looks from people across the parking lot anymore. The tread pattern is way more appropriate for driving on the street. And it appears to have a longer road life.
Off road, the R/T may have a different compound or something. They do great off road, everything I need it to do all of the time, but I did chew them up a little more than I thought I would mashing around at King of the Hammers.
However I was running full air pressure, instead of airing down for the rocks, so I suspect that was the main reason.