Justin Herbert or Mahomes?

[Chieftain]

Herbert has one major flaw: Lack of touch in his throws

He makes up for his lack of touch by throwing impressively accurate balls and doing so consistently even in tight windows.
You can only do that for so long in high pressure situations. That's when touch comes into play. And escapability, too. He doesn't leave the pocket as much as he should. These two combined play a deciding factor in him closing out games.