I dunno. That sounds a little too personal for me. I'd hate to get a business letter from a roofing supplier that was signed "yours faithfully." Sounds like we are in a relationship.
The traditional rule of etiquette in Britain is that a letter starting "Dear Sir or Madam" must end "Yours faithfully", while a letter starting "Dear " must end "Yours sincerely". In formal etiquete, not to use these formulaic expressions would be interpreted as ignorant. (Obviously this doesn't apply to close personal friends).
Things are different in the states. Over there, "yours s