Who wins?
Calling Uno on someone vs Challenging a Draw 4
Challenging a Draw 4 wins 51% to 49%. 106 more put them in the same row. From Board Game Rule Debates Tier List. Pick a side.
soggy_frog on Calling Uno on someone: catch them before the next player goes and they draw two
OldPigeon369 on Challenging a Draw 4: actually in the rules, show the hand if challenged
Board Game Rule Debates Tier List: the full ranking