My first pistol was a Sig P220 that I bought around 2011. Multiple parts breakage under 400 rounds occurred. It was sent back to Sig and repaired, but I never trusted it again and sold it immediately upon it's return. I think my P220 was a particularly bad gun, and I tried not to let it change the way I viewed Sig... but to say that the pistol was flawed is an understatement, and to say it didn't change my view of them is a half truth at best.
I was never into the 320s. They seemed neat, but didn't do anything (for me) that a Glock doesn't do. I can't honestly see myself changing modules all the time, so for me that seemed gimmicky. I wasn't shopping for a new pistol when the 320 came out, and I wouldn't have looked to them if I was.
Other gun companies have made mistakes and swept them under the rug as well. But with my personal bad experience with Sig, and their poor business practice, and dwindling reputation for quality I can't say that I'll ever be looking to them in the future. Regardless of the date of manufacture, model, or perceived use I won't be buying any Sig for at least a decade. Probably never.
-Cory