I have both. I'll echo what the others have said:

1. The SR9C has a manual safety and a magazine disconnect safety. The SD has no safety.
2. The SR9C comes with two 17-shot magazines. The SD comes with two 16-shot magazines. Fair enough.
3. The SR9C's barrel is just a tad shorter than the SD's.
4. The SR9C is about $130 more (where I'm at) than the SD.

I own both. I've had no problems whatsoever with either gun's functionality. No failures to fire, failures to extract, stovepipes, magazines coming out when I didn't want them to, nothing. The Ruger is more accurate. The SD has better slide serrations. Both have a well-textured grip. The Ruger has an ambidextrous safety and magazine release button. The SD is easier to take down. The Ruger's trigger seemed to lighten up quicker than the SD's. So...

I prefer the SR9C. I've been a Ruger guy all my life, and I think the Ruger feels more solid. Maybe that's just me. However, there's absolutely nothing wrong with the SD series, especially at the cost.

Gott dangit, let me take some side-by-side photos and get them up...

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