Steve,
Everyone has the fidanza. Aside from the stock OEM, there has not been another alternative it seems. The stock is larger, heavier, and steel. The Fidanza is aluminum and some have made mention that the softer metal may not be enough for the power our rigs put out. Other have no issues at all. If this new one had not come out, I would go with Fidanza. Now we have another option.
Plus the price is about the same for either. Fidanza will give you quicker launch but slower top speed. The DC will be better than stock off the line apparently, lighter, higher top speed, and stronger.
That is my interpretation of it. If I am wrong, someone comment.