I've run both.
MTRs- Run true to advertised size, handle rocks and mud well, have decent sidewall protection, wear evenly when aligned properly, have great road manners... even on wet roads, and are very quiet for such an aggressive tread pattern. Main drawback is that they can sometimes take a good deal of weight to balance, but that's generally in a larger size. 3 of my 37" MTR's took around 4oz but 1 took over 8oz.
KM2s- Run smaller than advertised size by about 1", handle rocks well/ do "okay" in mud, tend to chunk pretty bad on granite, wear evenly when properly aligned but tend to wear a bit faster than the MTR's, are louder than MTRs on-road... especially in larger sizes, handle pretty well on the street but tend to hydroplane more than MTR's on wet pavement, and generally balance easily without a ton of weight.
That's my experience. I would get the MTR's. I think that you'll be very pleased with them.