Had km2s on mine for about 3 years. They were ok but got louder as they wore and I rotated them almost every oil change. I sold them and now I have toyo mt's and these tires are awesome.

 

I am running 35inch MTRs they are quiet, and are wearing well. However I only have a few thousand miles on them but I am very happy. I would have to say my 35x12.50x15 are not true to size... Mine barely measure 34inches.

I ran the older MTR on my TJ and I was extremely happy with them, good tread life, kevlar side walls are awesome, pretty much the reason I bought them again for the JK.

I will say its probably a toss up, in my opinion they are both good tires. But I have torn sidewalls before on other tires, never on an MTR, not to say it can't happen. I like the extra sidewall protection just because once the sidewall gets a hole the tire is done...
Happened to me twice with Pro-Comp tires.

 

I'm running 37x12.5x17 KM2's and they work great for me. No vibration or noise. Great traction on the trails and thru the mud also.