This thread illustrates perfectly why I often recommend that newbies start out with a standard friction control bar.
With those you can miss the setup by quite a bit, and still get some benefit out of it... Naturally The better the setup, the better it will work.
The DC pretty much forces one to get the setup good... If the same effort was out into a friction control bar system, there would be a lot more favorable comments on them.
OTOH, I have noticed that the people that gravitate towards a hitch like the DC, are more likely to be the hands on type, that will stick with it until it is right.