Mahomes 15-3 in the postseason with 41 TD passes and 8 INT's
Allen is 5-5 with 21TD passes and 4 INT's.
If you add in rushing, you can argue Allen is better or same in both regular season and playoffs, there really is not a lot of difference in either. We could break down stats but they are both outstanding in the postseason. 15-3 vs 5-5 easily breaks the tie, 0-3 vs Allen vs Mahomes drives it home. All things considered you want the guy who is 0-3 vs the other guy who has been to what 5 straight AFC championship games, 4 SB's vs the guy who went to one championship game and lost to the other. What exactly are you considering?