The difference is the DC has "built in" sway control rendering the add on friction sway devices unnecessary and inferior.
Another good setup is the Equalizer Hitch which I currently run after graduating from the old EZ Lift setup with add on single friction sway control. I went with the Equalizer over the DC due to the design of the tongue on my new V Hull trailer. Both the DC and Equalizer are good hitches. You might want to add a friction control to your rig and see if it alleviates your concerns.
If not, scrap your current set up and go with one of the better hitches with built in sway control. FWIW, I ran the old EZ Lift setup with single friction sway control for about 9 years and it worked "OK". The Equalizer Hitch is like night and day.