Mine seems to cut in pretty easy. The other day leaving the self carwash, I needed to cut across lanes of traffic, to get into my direction lane. When I accelerated quickly while slight turning to the left (tires where still a little wet), I could feel the rear starting to let loose. The VDC light came on, slight power cut, and the car snapped back to center.

Its more difficult to lose control with it on but of course you can lose control. All systems have a limit to what they can handle.