I've owned my Sigma 9mm(about the same size as the SD9) for about 10yrs and have tried a few IWB holsters and most have just not worked or have been uncomfortable for me. I am constantly adjusting and feeling the gun "printing". I dont CCW this gun unless I really want to. I can carry it comfortable with a OWB Forbus quite well.

I recently purchased a M&P 40C and what a difference. Weight feels about the same, But the shorter slide and grips make a huge difference. I used the same Sigma IWB holsters and It carries extremely well and comfortable. No adjusting or "printing" and I can wear what ever I want when I CCW the M&P 40C. This is easily my #1 CCW. Size, 10+1 rounds and great accuracy.

Well worth the price of admission!

PS. I still won't part with my Sigma. Great for home defense. Just not versatile enough to CCW.