This is a stupid question.
Heracross obviously cause he's kick-a*s dual type with Megahorn and BrickBreak. Or alternatively, an Endure-->Reversal @Salac berry owns. Pinsir is no contest for Heracross cause it's so limited in almost every way.
In my opinion Heracross is better but Pinsir is so much better designed than Heracross. However Heracross has that 4x weakness to flying but he also has some gud moves including MEGAHORN. There arent tooo many good bug attacks and fortunately he has one of them.