There is a big difference between locking Diff, and LSD.
LSD relies on a wheel slippage to activate the wheel with grip. The problem with LSD systems is that in the event you are in an off camber situation, the LSD won't transfer the power correctly and you will just spin the tire in tire in the air.
But a locking diff, will physically lock the left and right axles together via electronic actuator or air actuator.
Where the LSD is better over locking is in the case of On Road driving. The LSD is always active if in the rear diff, a locking is not. In the case of LSD the diff will always catch a "slip" of one wheel. However, the hiccup to it is when turning. The outside wheel has to travel farther than the Inside wheel. this is bad on a locking diff and will actually break it. So don't ever use a locking diff on dry pavement.
FYI, ford LSD systems in the super duty are good, but what I have experienced is that for an odd reason the design of the 4WD system with electronic dash switch, isn't that great for "auto" mode.
Many ford owners never read the manual to understand that on a superduty equipped with LSD, just because it is in 4wd, doesn't mean it is "locked" in 4wd. You have to get out and turn the hubs in. Otherwise the "auto" system doesn't kick in until it detects a slip, which means the LSD system has to catch it too before the plunger moves to lock the wheel in.
People who own superduty ford trucks who say it gets stuck or they have issue, just never read the manual, so I would ignore what those people have to say about ford trucks.
My old 88 GM has the g80 option, and that thing will go places that is just insane.
