Welcome to the forum. Tell us a bit about yourself. What would your preference be?[emoji6]
It's really a personal choice. Some guys like cocked n locked, or the choice of hammer down, so that would be the B. Some don't want to manually lower the hammer on a live round, that would be the BD.
Then there's the ones in the middle that don't really care, and just use the one that jumps out at them. I'm one of those.
My first CZ was a BD, so that's what I buy, have no use for a safety, so really, there's no other reason than that.
Someday I'd like a SS, then I'll grab a B and never use the safety. [emoji87]