I think that the sword pilt pin has been 'done to death'.
Amen! My first kilt pin was a sword style, because that's what I saw everyone else wearing. Now I'm just plain sick of it. It's been overdone. I've changed to a simple 4" safety-pin (blanket pin) style. It's traditional and simple.

But I'd go for a round pin in an instant if I saw one I liked. They look pretty darn good, especially if they're worn a little higher up than usual. Like, say, at least halfway up the apron.