I had very high hopes for the BFGoodrich KM2 when it came out and planned on getting a set. Before I could justify it, a couple people I know got them and I got to see them on the trail. There is no question they're a great tire, not as good in the snow as the TrXus, but slightly better on rocks. Mostly a wash in my mind; where I really cared was the sidewall strength, something the KM2 promised to have in spades. I have not been impressed, however, seeing them on the trail. I've seen plenty tear the guts out of the sidewall.
The new Goodyear MT/R with Kevlar is a relative unknown, not to be confused with the old school MT/R. I've now put almost 5000 miles on a set and I have to say, that in my opinion, it is the best all around M/T currently available. Good on the road, good in the snow (again, not up to TrXus standards), amazing in the rocks, very good on muddy sloppy PNW trails and finally a sidewall that I can't break. A significantly better tire, IMHO.