They are very different beasts, to me anyways.
They are both very substantial in girth/circumfrence. The DTBM is more of a straight handle with a generous swell for palm that locks in the hand nicely saber grip. The FBM is more designed to allow numerous grip positions and I feel it does this quite well which affords it's popularity. Choking back to chop is the real shining ability for this knife, I like both knives well in general but the DTBM may be more of an all around use choice because the handle is straight and not optimized for chopping positions.