Black faces make components look like toys. No serious piece of electronics should obscure the surface markings with a black face. Think of all the lab equipment you've ever seen...consider the components in this MIT electrical engineering lab workspace:
https://www.google.com/url?sa=i&url=https%3A%2F%2Fedgerton.mit.edu%2Fclubs-teams%2Fmit-electroni...
Silver is functional, timeless, professional, serious.
https://www.google.com/url?sa=i&url=https%3A%2F%2Fedgerton.mit.edu%2Fclubs-teams%2Fmit-electroni...
Silver is functional, timeless, professional, serious.