I'm not in the market for a 45 acp right now and your question is one of the reasons why. I would love to have either one. The Sig C-3 just keeps calling my name everytime I see one. The S&W E series keeps E-mailing me telling me what a great gun it is.
I can't help with your dilemma, but I can say you have excellant taste in guns. Out of the box maybe the S&W, but that C-3 keeps calling my name.