Angron Red Clear vs Ember Orange

How close are they?

ΔE 21.7, loose: different enough that you should pick on purpose. Ember Orange is a little lighter, much more saturated than Angron Red Clear.

Can I use Ember Orange instead of Angron Red Clear?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Ember Orange is a little lighter, much more saturated than Angron Red Clear.

Can I use Angron Red Clear instead of Ember Orange?

The same difference applies the other way round: Angron Red Clear is a little darker, much more muted.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.