Grim Tuesday
Smash Legend
Nair works equally as well as Bair when approaching against Marth, but only when you are sure it won't be punished.
When you are trying to bait him into using a fair/double jump/fsmash, bair is much safer due to it's hit-box staying out 9 frames longer and the way it moves you in the air being less of a commitment. You can hit him with it and combo the same way as nair.
It works against some other characters... Peach, Sheik and Ice Climbers immediately come to mind... Possibly more.
When you are trying to bait him into using a fair/double jump/fsmash, bair is much safer due to it's hit-box staying out 9 frames longer and the way it moves you in the air being less of a commitment. You can hit him with it and combo the same way as nair.
It works against some other characters... Peach, Sheik and Ice Climbers immediately come to mind... Possibly more.