Q1. - don't know. I've never had just a front LSD.
Q2. - tru trac is torque biasing. Torque to wheel with traction can be about 3 times traction at the other wheel.
So good even if low traction on one wheel, but not as good as selectable lockers. The trick if you lift a wheel, is to dab the brakes with your left foot - that will usually get you past that point.
Q3. - don't know much about no spins and have never had one.
I have tru trac f&r on my disco - because I wanted stronger diffs, wanted to try them and didn't need selectable lockers for the intended use.
ARB lockers f&r on the rangie - because they were about the only selectable locker I could get for the diffs I'm using.
Manual lockers f&r on the bushie - because they were factory fitted to the diffs I'm using (originally vacuum operated, but converting to cable).

