I also have been running the BFG KM2s on my '96 ZJ and have been happy with them.
I have heard about sidewall defects in the Goodyear MTRs but do not know for sure how extensive this is.
I can tell you this, I have been on two of the longer Jeep trips this year so far with another club, one to Moab, UT and one to Death Valley, CA. On both of those trips I witnessed two different Jeeps, both with Goodyear MTRs have a tire failure due to what appeared to be a sidewall defect. On the last trip the tires were aired down to around 16 lbs and the sidewall cord ripped and was poking out of the sidewall. It appeared as though the tire was not damaged from outside the sidewall as there were no cuts, or marks on the sidewall at the spot where it failed.
I would do some more research on the Goodyear MTRs before making your switch.
Woody