I've used mine so much at one point, a warning light came up saying "over temp" or "abs hot"??...I don't remember for sure what the light was..... It's a pretty cool feature, but really limited as to when it's really needed I think. You can drop down some pretty steep hills and the hill decent will surprise you how well it works though, you learn how to feather the throttle to control the braking, after a bit of use, you can smoothly operate the feature when on a long decent.

 

There are descents that are either dangerous or impossible without some kind of HDC, just too steep and loose. A person can't brake the rear brakes enough and the front brakes grab more and the vehicle will roll. An expert might be able to control the extreme fish tailing, but I've seen a Disco roll many times because the driver touched the brake and accidently disengaged HDC.
Land Rover dealers fault as they led the off road experience and didn't inform the driver well enough what happens if you use the brake.