I've had my Sigma 40 for several years. I have not had any problems. The trigger pull is not a problem. They tault us to squeeze the trigger and be surprised when it fires. Every time I pull it, it goes bang. It shoots good enough that at self defense range you can put them all in the 7 circle...
A little gun oil and a brass brush will do wonders for any finish. The brass will not scratch or cause rust. Steel wool on stainless can cause rust to form on stainless. Light oil is the key.