So, I have a 6D and a D600 in hand right now...

Only when your camera is switched off does it matter. Otherwise, just look at the screen.

For having used both a D700 and a 5DIII, I can certainly say that it's not the case at all. Strictly in terms of changing the drive mode, it's basically the same speed, but in addition to that, you have to change your handling of the camera on the Nikon solution, which you don't have to do on the Canon. Try changing drive modes when they're both fitted with heavy telephotos.

If by that you mean that it's not that subjective, I agree.

It's worse in every way apart from being able to look what drive mode is engaged when the camera is switched off.

As I just said, it also makes it impossible to save drive modes in custom modes. As somebody else said, it makes combining different modes impossible (like mirror lock-up with timer).