I've had one in my XJ for almost 3 years. Right when I put it in it busted off the tab on the alignment spacer or whatever it's called, then they warrantied it and gave me a new one. It seems like that happens to most people who put em in an 8.25, then no more problems after that. I used it for a year on 31s and a year and a half on 35s and it took everything I threw at it. It served me great for both DD and wheeling. It only had the harsh engagement/disengagement like 10 times the whole time I've run it. Very predictable and nice to have. Pretty quiet and smooth too. I wouldn't hesitate to put one in a DD again.
I have yet to run an Aussie locker, but I've heard nothing but good things about them. If I buy another lunchbox locker that'll be it. Great price, great warranty, and from what I've heard great dependability.