I have had an Aussie in the front of my TJ for a few years now and haven't had too much trouble. When I put a lunchbox locker in my old XJ years ago though I broke several sets. And yes, when the u-joint breaks it usually takes out everything in it's path, mostly the ears of the inner and outer shafts. One of the things that I quickly learned I was doing wrong was I usually broke when the joint was in a bind, mostly when the wheel was turned all of the way to one side and the tire was against a solid obstacle. In my XJ I adjusted my turn stops out so it would bind the u-joint so much, but since my TJ is my daily driver I am just more cautious. Most importantly though, if you do break a u-joint or axle shaft, make sure you don't try to drive it without the stub shaft in the hub. There was a guy and his father that died a few years ago after they broke a shaft at the Badlands in Attica IN, they pulled the broken shaft and headed home,with nothing holding it together the unit bearing gave out while they were going through a curve and the Jeep rolled.