The Diesel Dynamics box is manufactured by Edge products.
If I remember right Katdiesel did a comparison a while back on the dyno Drag comp vs. DDUFM and both boxes performed within 7 or 8 horsepower each other.
From what I hear the DD box has a little less fuel timing advancement.
So, it might run a little smoother and not smoke as much.
The Edge box ultimately came out on top.
But, either is great box.
--Justin