ΔE 11.9, fair: the same colour family, but not a straight swap. Muddy Brown is more muted than Dark Wood. They are different kinds of paint: Army Painter Dark Wood is a one-coat contrast-style paint and Reaper Muddy Brown is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Muddy Brown is more muted than Dark Wood. They are different kinds of paint.
The same difference applies the other way round: Dark Wood is more saturated.
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 Dark Wood on the colour wheel See Muddy Brown on the colour wheel
All matches: Dark Wood equivalents · Muddy Brown equivalents