I been running the 3J LSD for about 15k miles, very happy with it. Just so your prepared, the diff did not fit in my trans case, so i had to grind inside of case a little.
I have no prior experience with LSDs, it makes some clunk noises when turning left at low speed.
The most difference i notice with this LSD is when accelerating out of corners. It pulls into the corner.
Using motul gear 300 LS, Im planning to change it every 15k or so, the first change after run-in should be much earlier I read.