I've never fired a Sigma, but I know that they are S&W's "budget-friendly" line of pistols. The only thing I would suggest is to put a few thousand rounds down your's and see how it's hold up.
Their M&P pistols are made to compete with Glocks and that's probably a better comparison. I didn't like the M&P trigger, but did like everything else about it.
Their M&P pistols are made to compete with Glocks and that's probably a better comparison. I didn't like the M&P trigger, but did like everything else about it.