After i first began emulating i can say that keyboard wins on controls only because you can customize it to your own finger positions (for those who don't like using the home row style finger placement).

Since i use the home row style finger placement ive found so many games to be alot easier to play like smash bros and any ds game (ive seen where the buttons are placed and i don't like).

However whenever it comes to button mashers and analog control games i have to go with controller.