ΔE 9.2, close: similar, with a visible difference side by side. Bugman's Glow is a little lighter, more muted than Viper Brown.
✓ Army Painter Fanatic conversion chart lists these two as equivalents.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Bugman's Glow is a little lighter, more muted than Viper Brown.
The same difference applies the other way round: Viper Brown is a little darker, 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 Viper Brown on the colour wheel See Bugman's Glow on the colour wheel
All matches: Viper Brown equivalents · Bugman's Glow equivalents