The reason I love BBF so much is that it really allows you to take advantage of full time manual focus. Otherwise, when you touch the shutter again you are fighting yourself. It really shines with weaker AF cameras like the 5DII, as I use center point AF to grab focus, then recompose and tweak focus manually while shooting. Really increases hit rate with shallow DOF shots.
There is a Best Buy store in NYC by my office. As I work in developing consumer products, I like to pop in there from time to time to do market research. The Canon M system never appeared in that store! How can a new system like that ever get off the ground if it isn't supported by a big box store like Best Buy?
The camera section continues to get smaller as their tablet section continues to grow.