I guess I don't really see why it's a copy of the glock. It's a polymer framed DA. (shrug) If it is, so be it, though it's a poor copy in my opinion.
I found (and continue to find) the gun to be unreliable and unaccurate. (No, I don't own one, but have had the displeasure of shooting a few on occasion.) The trigger on the Sigma is beyond bad. No comparison to the Glock there. The fit is terrible. Construction quality is poor to fair at best. Reliability? I've shot one that only had two malfs out of 100 rounds (which is still terrible) but the second I played with had at least 3-4 malfs per mag with multiple types of ammo. But then again, it's a cheap lil' DA. S&W has never made good autos, and the Sigma is their bargain basement version of their more expensive "tactical" models. (Which, in my opinion, are also junk.)
I've run into very few shooters (almost none) who have anything kind to say about the Sigma. You did mention in your post that you have a Kimber 1911 so I have to assume that you've shot at least a few different guns. "To each his own," I suppose, but there are MUCH finer guns out there, that don't cost more than the Sigma. Kahr, Glock and H&K are 900% better guns.
All that being said, I realize I've really disparaged your gun and I apologize in advance for it. It drives me nuts when someone "trash talks" a gun but in my opinion, the Sigma is one of the very few guns in the world that have almost no redeeming qualities. And I'd have to say that every shooter I've ever known who's either owned one or tried one has hated it. (Except for you, of course.
) But once again, let me say that if the gun works for you, then keep using it. The above is my opinion only from experience with this piece.
Best wishes,
-Ryan