The real problem with Controller vs Keyboard/mouse is the ability allocation space.
With a keyboard you have basically as much as you want (well up to about 96~ slots) with the controller you only have sets of 16 which have to be swapped, I certainly wouldn't recommend more than two sets for any job since cycling between them will take time and can cause you to misfire abilities in the middle of battle.
However the controller let you move, use abilities and control the camera, all at the same time. Additionally you have a 16 directions analog movement in a single finger while keyboard users have to deal with only 8 direction digital movement that requires 3 fingers. In short keyboard gives you better ability control while the pad is superior for movement and multi-tasking (keyboard users have a very limited ability access while moving)
At the end is personal preference and commodity, perhaps the best idea is to try both systems and choose whatever satisfies you the most, both have their pros and cons.
Finally there are some keypads out there (for example G13 of Logitech) which try to combine the best of both worlds.
____________________________"Maybe it means: you're the evil man, and I'm the righteous man, and Mr. Nine-millimeter here, he's the shepherd protecting my righteous *** in the Valley of Darkness."
- Jules. FFXIV: Mabel Rand (Gugnir)
FFXI: Kenage, retired.