Goku can react faster than anyone right now in the manga, he also can use hakai, on the other hand, luffy has just achieved *spoiler* ryou and advanced color of observation haki. Still, luffy couldn't dodge a hit from Big Mom who is at her best, a raging lunatic. She might be even god level like kaido because of her powers, that is what people don't see. Coming back to the original post, if you asked the biased me, I will say Luffy, although we all know it's Goku for now. Until and unless luffy awakens his devil fruit, he will never be a match for someone like goku. MUI is not just predicting the flow of the fight, MUI is literally reacting at the speed which is inconceivable to people. Jiren and goku were so fast that nobody could even see them anymore. Any science or engineering grad can tell you that means they are reacting and fighting and at speed higher than the speed of sound and maybe even at mach 10 or more. Luffy can come near that once he perfects snake man but without haki he will never even phase goku. So let's wait and watch but this bout goes to goku.