[wingnut60]

Terry,
The real answer is for you to try it on I-40 in an open area just to see how you like it. I believe that you will eventually find that it just isn't a practical use of that option.
As for me and my last F350 and now my 450--I just don't like it except for short periods on flat stretches of wide hiways to maybe give my right foot a rest--and the cruise tends to lose too much speed on the uphills and then floors the throttle to catch up--not good for mileage.
And I can get better mileage if I want to without it--the cruise can't anticipate long downhills or get a run at a long uphill.
Joe