I don't have a FFBM but what I do have is a FFFBM that would be more of a comparison with the NMFSH.
FFFBM-10" Flat Grind, .320", Pumpkin G-10, Black Crinkle coat
NMFSH-9.5" Flat Grind, .320", Black Micarta, Black Crinkle coat
I used my wife's crochet needles to run through the hilts to show the example of what I'm talking about and using them to keep the hilt some what aligned.
Pic #1, Pommel view is one of the best cause it shows the Block form of the G-10 vs the EXCELLENT rounding on the Micarta. Busse Shop I think over time has realized the comfort in the rounded shoulders of the hilts.
Pic #2, Again you can see the roundness of the hilt shoulders. Also, with the crochet needle in the talon hole notch that the FFFBM sage down more therefore showing the FFFBM is slightly heavier. ***(IMHO not enough to make a difference)
Pic #3, Shows the tip is 1/2" longer and of coarse the blades distinct shape difference of a Clip to a Drop point
Pic #4, Finally you can see the choil size difference.
Personally I love my FFFBM, this one I haven't used but I really like them.
BUT I have to say I feel that If I'm going out to swing a knife for a while this NMFSM is going to be hard to beat in the Micarta line (I am not talking RES-C)... The overall comfort, wielding etc The NM Line, NMFBM, NMFSH and the NMSFNO are going to be hard to beat in the use department.