I'm familiar with both parts, I've been once in my lifetime a controller player, when I went home from school I would go directly play Doom or half life on my computer (using a gamepad). But I always noticed some sort of inefficiency on the gamepad during the gameplays. I now play on a PC, and I find the mouse and keyboard significantly better. With the mouse I'm capable of pointing at different coordinates a lot quicker, I type a whole lot faster with the keyboard, and I find giant visible disadvantages on the Gamepad.
Firstly, and most obviously your evidence for the pro position is entirely anecdotal. Therefore my first point would be that, given a keyboard and mouse has been found to be faster and more efficient for one person, is this the same for everybody? Consider a one armed man. Consider a person at is entirely used to the use of a controller. Clearly in these situations a mouse and keyboard would be neither fast nor efficient for those particular people.
Secondly consider suitability and design. Menu's designed with controllers in mind offer relatively poorer performance when used with a keyboard and mouse. Consider a game like Skyrim where the original design of the menu has been completely modded out by a large portion of PC players to favour a mouse and keyboard playstyle. Therefore it is not correct to say that mouse and keyboards are faster/more efficient than controllers.
Finally, a controller has less than 20 buttons. A keyboard alone has more. Thus it has a higher learning curve.