I`m a bolt release guy. I`ve been practicing it long enough that it`s the fastest method for me. I find using the charging handle to be a lot of movement, moving your whole arm and hand to actuate the CH as opposed to just pushing a button. But, that`s not to say using the CH might not be as fast if you train that way.
I`m personally not convinced in the whole `charge the rifle like you would rack the slide on your pistol` theory (not saying it`s wrong, mind). I think if you`re consistent in the manner you train with both your pistol and rifle it might not matter.
Obviously it`s a personal preference thing, I don`t think either one is better than the other. For example, someone with weak arm strength might find it much easier to have support of both their arms to push the bolt release than have the entire weight of the rifle on just one arm.
One thing is for sure, I`m not a big fan of BAD levers. Great in theory, but I`ve seen a few of them cause some pretty hefty and constant malfunctions (ie. constant failures to feed). I don`t have faith in their reliability.