I don't feel like you can as effectively do stuff like this;
http://www.perfect-dodge.com/Example.avi
with a keyboard, at least not to the degree you can with a controller, and definitely not imho with the same ease.
I will say in support of a keyboard that, it sometimes takes a second for the pallet to come up on a controller; this is infuriating, I have no clue why it's like this, but it feels like you'd know your macros really well on a keyboard and be able to Alt+whatever which I'm pretty sure goes off even if the onscreen pallet lags a bit.