I guess the consensus is to keep DSC on unless additional traction is needed in the situations where additional traction is needed for snow/icy/muddy spots.
I did use the Hill Decent Control quite a bit but it was not all that practical. Every time you turn it on, it defaults to 5 MPH and it maxed out at 16 MPH. So you had to slow way down to enable it smoothly and then max out the speed to 16 using the speed control button. In many situations I would have like it to go up to 20 or 25 MPH.
Here's some PICs from the trip:
http://flickr.com/gp/9525655@N06/6w3057/