Make sure
Make sure the Sigma you're getting is the recent generation of them (3rd gen, I think?) The earlier Sigmas have bad reps. I've seen many a thread dealing with that issue. My 40 Sigma is recent manufacture and I have had almost no trouble with it. A few light primer strikes, but that was on ammunition that seemed to be iffy. Only one FTF on a winchester case primer, and I think that was due to an out of battery trigger pull. It was the second box of ammo I used, so I can't really recall the exact details, but the thing absolutely loves CCI. The heavy trigger pull is terrible for range shooting, but between my M&P and my Sigma, I'd probably rather every-day carry the Sigma. Keep it chambered and I doubt, short of a bad holster or unsafe grip, the thing will go off.