Dont know, my navy suit is darker than my SC. Also it is quite a bit more formal with besom pockets. I generally wear it to night time weddings etc, with a white shirt and a navy/silver tie. Anyways, post a pic of navy suit that you think is done well ...
If it was a choice between grey and navy, only a tiny minority would choose grey?
I think that's a tricky question because while there are more shades of grey that look good than there are shades of navy/blue.
Personally I think navy suits look better than charcoal suits, at least on me, and I have an easier time pairing ties and other accessories to navy than charcoal. But that distinction goes out the window when we switch to mid grey.
So, my hierarchy:
Navy = mid grey: Looks great, is subtle and understated; I could get by on nothing but these two.
Light grey: Looks great but tends to stick out more, not as understated as navy/mid grey so somewhat less versatile.
Charcoal: Classic and understated but I don't like the way it looks on me; I have one and that's all I need.
Air force blue: Doesn't look as nice as navy and tends to stick out. I like this color in theory, and on others, but doubt I'll ever get a suit made up in it becuase I'll always wind up picking a navy suit over it.