Save your money and buy a Glock 19, new or used.
Sigma will not live up to the expectations of someone who has had Glocks.
XDs, I am told, are fine guns, but the tinkerer in me is disappointed that there are no aftermarket parts available and Springfield is very niggardly about shipping spare parts.
My M&P is a fine gun, but the Glock beats it on value.
In my experience, a good Taurus is a good gun, but a bad taurus is a nightmare when it comes to getting parts or repairs. Customer service is not the strong suit of that company. I will never have another one in my safe after it took over a year for Taurus to ship a spare part to my gunplumber.
Buy the glock, you will still be happy 20 years from now.