What games do you find are better using the controller rather than the K&M?
I'm debating getting one myself.
I personally found the following types of games "better" for the controller:
RPG/Shooter: Mass Effect series (I unfortunately started on the XBox/X360, so it was automatic for me as a continuation of muscle memory)
Fighting: Street Fighter series (better with proper 6/8 button fight stick controller, but can't be bothered to grab one, so controller better)
Fighting: Dead or Alive series (again, started on the XBox/X360, so automatic continuation)
Top Down RPG type: Ninja Gaiden series (started off on XBox/X360, again automatic continuation)
Top Down RPG type: Dungeon Hunter series (started off on mobile, and thus continuation of muscle memory control)
Puzzle type: Tetris, Hexic 3D, etc.
So really, mostly games that started off on different platforms that were controller based, or games that you really can't do : ->, \], ->, light punch, medium punch + medium kick, -> ->, light punch, v, \], ->, v, \], ->, all punches, then realise you fluffed the combo and about to be taken out and need to react and not being able to because the directional controls on the keyboard is simply not responsive enough. Or games that are more leisurely and don't need many input commands.