As I understand it from just reading, the traction control just monitors rear wheel slip and applies the brakes and or decreases power to prevent too much slippage.
Autotrac has sensors in the car that monitor motion I think in the X and Y directions. it also has sensors to monitor slippage of the rear wheels. It does more than traction control. If it detects a skid it applies any or all the ABS brakes and decreases power to help prevent loss of control.
I have read that the DOT for USA plans to make Stability controls(like Autotrac) mandatory in a few years since it significantly decreases the odds of a driver getting out of control.
I have not had too much experiecne with the 2004 LSV8 I own as far as getting out of control and maybe that is the point. I have only felt what I think was Autotrac taking over once, just a few weeks ago. I was passing a slow truck in a driving rain with standing water and going probably too fast. I felt a momentary tail squiggle like you may get just before the car floats away like a jet ski. But just a split second after the squiggle the car was back in control and moving just fine. I think it was working but can't be sure and like I said, I think that is the point.
One negative of either is that if you are an enthusiastic driver, these systems may prevent you from maximizing your fun if you know how to drive on the edge. That is why there is an off switch.
Most of us do NOT know how to drive on the edge and that is why stability controls are becoming more popular and maybe mandatory.
There is a cool video somewhere on the web about the Mitsubishi Evoc in Europe. In the video they show how the stability control allows the driver to drive all out and keep up and even fluster I think a Ferrari or some other exotic. That little rice burner was just scooting around the track and maintaining very good control while the other car eventually spun out.
Just my reading and little experience,
Jim Henderson