Mihawk.
Kizaru is fast when he's travelling in light form but when he strikes he materializes and with Mihawk's famous eyes, he should be able to react to his moves if anyone. His ranged attacks, Mihawk would be able to dodge with his insane physique and reaction. For offense, Mihawk is probably both faster (in regular form) and stronger except for his ranged attack which is slower.
For endurance, Kizaru wins, but this wouldn't be that long of a fight although Mihawk would win high difficulty.
Just my opinion