As a glock copy, the sigma is functional. The trigger is so bad, however, that I would recommend against it. Even with better springs and a trigger job, it is still not a very good trigger. I have a coworker (older woman) that bought one. She thought the trigger pull was okay, but when I took her to the range, she tired of pulling the trigger after two magazines. I took it home with me and tried to clean up the trigger and change the springs, but the difference was not enough. She has since sold the gun and bought a glock and is much happier. I'm not the biggest glock guy, but the trigger is much better than the sigma.
Personally, I'm a walther ppq guy right now, when I'm not a CZ P01 guy.