What are the advantages of approaching with nair vs dair?

[VeraMar]

Title pretty much says it all.. When is it a good/bad time to approach with nair and dair?

 

[MH | Joeschmo]

Nair is a much safer option against opponents who don't crouch cancel or at a percent where cc doesn't work. It leads into shine if missed so I find it to be a better option at higher percents and a safer way to get in a shine. Not to mention it is safer on shield when spaced and timed correctly. Dair is better at lower and mid percents as it negates cc and leads into pillar combos, plus having insane priority will beat out most attempts to counter your approach. As far as situations, what option is better hard to answer as examples x or y situation would be needed. If you'd like you should name some situations that you don't quite know which aerial to use and I'll try to explain and rationalize which is better in those particular situations.