I have two OM Zuiko 50mm/f1.4s. the "black nose" one has a very nice blue-ish coating but the "silver nose" one has a completely different looking "gold" coloured coating. Both lenses perform very well but the "silver nose" seems slightly less critically sharp and a bit less contrasty which comes in useful when shooting in sunlight - hence the reason I've kept both.

Otherwise, I have a Nikkor AF-D 85mm/f1.8 and AF-D 50mm/f1.4 whic have beautiful purple and blue coloured coatings.