I own a Sigma SW40VE, which was produced later in the production run! With over 3000 rounds through it, never a failure to feed or fire when the trigger is pulled! The only thing I have done to it is change the front sight to aftermarket fiber optic. My buddy with a Glock, has fired this gun, and likes it as much as his Glock! Guess if you are looking at the Sigma, try and get one with the later serial numbers!
If you have one that is crap, or that one calls crap, first check your grip! These guns, like many semi's do not like a sloppy weak grip! Too many times at the range I have seen people with weapons that are not cycling correctly, and they blame the gun when they have a weak grip not allowing it to cycle correctly. Several times I have offered to help, take a good look at the weapon, put in a fresh clip and fire off 5 rounds, 10 rounds without an issue! Then show the owner the proper way to hold it. Problem solved!
Next, if you are not happy with it, send it to S&W and have them take a look at it! But make sure to clean it properly first! Would not be good for S&W to charge you a cleaning fee for a perfectly good weapon!
Greetings!