I bought a S&W 500 a few years back and at the time S&W was running a special where if you bought a new 500 you could purchase a Sigma for $50. I think they were going for around $300-$350 back then so I figured how could I go wrong and got one in .40. I'd heard they had a pretty heavy trigger in them but for $50 thought even if it's a complete POS it was, easily, worth taking a chance. Since I got it so cheap I planned on trading/selling it and I certainly never thought I'd be saying this but I still have it and that thing has NEVER missed a single beat. It does have a heavy trigger but it reliably eats anything and everything I've ever fed it and it shoots straight.
The new version, IMO, is a much better looking gun and I've read the trigger is better than the older version like I have. Mine has done everything I've ever asked it to do, and then some. The newer version does all that and looks better as well as has a little better trigger, heck, what's not to like.