Nice. How does it compare to the M9 LE that you had, or even the M9 CG?
Pretty similar balance wise - both are light and fast. I like the BWBM's handle better - it feels more secure in hand, although it does give a bit of the Busse pinky. I like the tip on the BWBM better too. The tip of the M9LE felt kind of thin and it seemed like it would be easy to break.
When I knew the BWBM was coming, I sold my M9LE to raise funds for it. I think it was a wise decision... the BWBM is fast becoming one of my favorite knives, possibly my overall favorite period.
And no, I didn't notice any flexing at all while chopping. I saw it flex once or twice when the blade went REALLY deep on a chop and I had to wiggle it to get it free, but that's it.