S'field also has the XD45 Mod 2 out. It's pretty much the same as the XDm except for grip texture, front sight and length. It's 6.5" long vs. 6.9" long. Capacity is the same. I've seen the 9mm Mod 2 for $440, so the .45 will probably be about the same, making it likely to be $75-$100 less than the XDm model.
I had an XD9sc about 5 years ago and shot a friend's on Sat. I'd forgotten how good that gun is. Very good feel and very accurate.