I can only compare to the rag joint set up and in that case there is no question - the adaper rocks. Much easier to work with, adjustable, and looks a lot more professional and clean.
The only problem I have is I may still need to bend the coaster brake a tiny bit because the chain is hitting the tire just slightly. On a bike with smaller tires this wouldn't be an issue OR a bike with a little more clearance between the tire and frame. I want the bigger tires but they barely clear the frame so I have no wiggle room. If I bend the brake just a tad I can move the sprocket out just a hair more and I should be good to go.