ΔE 9.0, close: similar, with a visible difference side by side. Burnt Sienna is a little darker, more saturated, warmer than Ruddy Terra.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Burnt Sienna is a little darker, more saturated, warmer than Ruddy Terra.
The same difference applies the other way round: Ruddy Terra is a little lighter, more muted, cooler.
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.
See Ruddy Terra on the colour wheel See Burnt Sienna on the colour wheel
All matches: Ruddy Terra equivalents · Burnt Sienna equivalents