There's a lot of variability when it comes to buying internal 1911 extractors. They can require tuning, too. They can also lose tension if they have to jump over a case rim in a malfunction clearance situation. I've seen it require anywhere from only one such instance, to a few instances, in order for an individual internal extractor to loose enough tension to start exhibiting extraction issues. Then again, quality of various internal extractors can vary.
The S&W external extractor seems to run pretty well. They do potentially require fitting when installing, just like the S&W 3rd gen guns, using a bar gauge to check for fit and a force dial gauge to check for extractor tension. There's also a heavier extractor spring available if a particular gun might require it.
I've been told that S&W is apparently working on yet a further improvement to their SW1911 extractor, which isn't unusual considering they're always revising and improving their parts in some manner or other.
Their Performance Center 1911's, and their newest 3" Pro Series Subcompact, also utilize an oversize extractor. I can see the potential need for it on a 3" 1911 with fast slide cycling and reduced slide mass. As some makers have discovered, it's not easy to get the diminutive 1911's to run well.
Here's a picture of the extractor hook of the typical SW1911 which shows the nicely done machining and bevel incorporated in the extractor hook to aid in feeding. (It's a .40 extractor from their 3rd gen line, which means it was originally designed to work well with the faster cycling and harder recoiling .40 S&W cartridge.)
My own SW1911SC 5" gun has run very reliably when using an assortment of duty JHP loads over the last few years that I've owned it. It just runs, whether it's clean or somewhat dirty from having fired a few hundred rounds over more than one range session. Other folks I know who own and carry SW1911's for off-duty have also experienced excellent results. There was one guy who bought one of the first production SW1911PD's who experienced some issues. S&W determined that there was a machining issue with his frame (back when they were first machining Scandium aluminum frames for the SW1911PD's) and cheerfully replaced the gun with a new one, which ran very well.
I'm planning to buy another SW1911 of some sort next year, which will give me 2 SW1911's and 4 Colts. I haven't decided yet which model I'll choose, but I've actually been thinking about maybe picking up one of the hand-built PC models. I've never bothered to own a hand-built model, being mostly interested in "working guns" over the years, and some of the PC models have come to interest me. Then again, the regular production SW1911 ES model interests me, too.
I was a bit skeptical when S&W originally announced it was getting into the 1911 business, but after having seen how well they've done, and the money they've invested in new equipment and engineering work, I've been very impressed with their 1911 line, overall.
Their armorer manual is a bit more in depth in some ways than the Colt Model O Pistol Model armorer manual I have as a Colt armorer, and I like the way they've set up their firing pin safety.
I expect they'll only continue to get better.