#1. "RE: Is the new sigma 180mm f2.8 os macro worth it?" In response to Reply # 0
I have the older 180 f/3.5 and like the focal length for subjects you don't want to, or can't, get close to. That lens produces a very good image. I even used it for a wedding once.
Because of the FL, I am generally shoot with this lens on a tripod, so I'm not sure having OS would be that useful. However, the wider aperture and a more up-to-date optical formula would be appealing.
So, if I didn't have the older version, I'd be tempted to buy the new one. But I don't think I will upgrade.