not in a nutshell: infernape got higher base speed and a bigger movepoool, different from blaziken he learn a reliable grass move to kill bulky waters, the fire types worst enemy, he also get nasty plot and CC, with both on the same set and other 2 special moves you can break all common special walls and sweep with +2 fire blasts, something blaziken cannot do.
in a nutshell:exactly what haunter said, higher speed and wider learnset let him deal with some pokemons more easily, thus he is overall superior.