I'd take a bcm all day over a dd.
When it gets to the point of BCM vs FN vs dd vs Barrett.... I'd take any of the above. Especially when you are talking mil spec guts. At that point it's just preference on the rail, barrel, and twist. I've had abcm and was always underwhelmed with it's ability on paper. I'm sure they are a fine defensive choice, but the groups I'm getting out of the ddm4a1 are downright impressive for a 14.5 and the rail is probably the most robust I've ever had.