ΔE 3.6, very close: most people won’t see a difference side by side. Quinacridone Crimson is a little darker than Evil Sunz Scarlet.
Can I use Quinacridone Crimson instead of Evil Sunz Scarlet?
Yes, for most jobs. Very close match (ΔE 4). Quinacridone Crimson is a little darker than Evil Sunz Scarlet.
Can I use Evil Sunz Scarlet instead of Quinacridone Crimson?
The same difference applies the other way round: Evil Sunz Scarlet is a little lighter.
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.