I have one I bought new in 1987 so it has all the bad stuff mentioned above: internal extractor, folded slide, roll pinned breech block. It's a magnificent handgun and just as (if not more) reliable as any auto I have ever used.
I've never heard about extractor problems wit the 220. I guess mine must always have been in spec.
rellascout highlighted most of the info ...
The earlier production 220's received revisions to enhance their durability over the years. I remember when what was later deemed to have been a production run of improperly tempered internal extractors (in the folded slides using pinned breech blocks) surfaced many years ago (a local sheriff's office DQ'd the ones their folks were using because of problems on the range until the extractors could be replaced).
In more recent years, the armorer instructor in the Sig pistol armorer class a few years ago told us to check the 220 frame inserts (steel insert the barrel's feedramp lug impacts during firing) for cracks periodically, especially if +P loads were used.
He said the only issue with the internal external extractor used in solid machined slides (meaning the American built 220's) was that the extractor was made overly tensioned so it could be installed, and then typically have the proper remaining tension after installation needed to provide optimal feeding & extraction. It was only intended to be installed once, though, and we were told to replace them if they were ever removed (after the initial installation). Apparently, Sig experienced some small number of instances where the tension didn't end up in the right range after installation, and some feeding issues were reported.
I also remember asking during the class why Sig engineers hadn't come up with an external extractor similar to what was being used in the 9/.40/.357 guns, since it had demonstrated it worked so well. I was answered with a shrug, and told that it was a good question.
Then, a little while later ... we started seeing the 220's coming with external extractors, so apparently they got around to making the same observation.
I don't have any personal experience with the newest 220 models (haven't updated my certification with Sig).
I noticed they decided to go back to the earlier roll pins (versus the solid pins), though.