My BD breaks incredibly clean in single action, especially after a couple hundred rounds.
There's no grit in the double action, but it's long and heavy.
If you're carrying the B, it's probably with the safety on in single action only. If you're carrying the BD, you're likely going to decock so the first shot is in double action and every shot after will be single action.
I got the BD because I don't like the thought of carrying a gun with a safety. I should be able to grab it and fire. The longer, heavier first shot makes this safer.
I'm now a contributing writer offering my take on hunting and firearms at the Good Game Hunting Blog. If you like what I have to say here, drop by and see more of my writing