Now this is a very close debate. Both have very similar skill sets, both are about the same in terms of stats, and both take a similar approach to attacking their victims. However, one of The Trapper's biggest weaknesses is the fact that he makes a lot of noise when he goes on the attack with his chainsaw, which can be turned against him by Springtrap.
Springtrap is a very sneaky character, able to hide in the shadows of the security cameras even better than Freddy could in the first game, and this sneaky behavior would help him in the long run. Add to this the fact that this is taking place in Springtrap's home turf, and he may even be able to have the Phantom animatronics help him here, and Springtrap may have the advantage.
However, this would be extremely difficult for him, as the Trapper does have his chainsaw, which will slice into him if he makes a bad move, and if he gets caught in a bear trap, despite him not feeling any pain, it would take him at least a minute or so to get himself out, more than enough time for the Trapper to take advantage of his opponent's weakness.
However, in the end, I will give my vote to Springtrap due to the home court advantage, and his higher endurance. Plus, considering how careful he is, I would imagine he wouldn't accidentally bumble into one of the bear traps, as those things are very big and pretty obvious, especially in a building where they're completely out of place.
Winner: Springtrap