Thanks for the report MikeO, as a full size M+P .40 owner for some time now, and other S&W pistols, It's good to see a continuation of a good thing.
I remember when the first Sigma's came out, they were not a Glock, and for right handers only, but it was the "plastic fantastic push" when Glock sales started rocketing.
The 4006, 411 line were extremely popular, and very reliable. Now they have more or less gone to the M+P, and it seems the new SD40, will be the extension/merger of the Sigma evolution.
Good to know, at that price,....

Hmmmm