Kimber botched the external extractors by making them too short. Instead of correcting them they just ditched them. I primarily blame Kimber for the bad rap external extractors have gotten.
I have a Dan Wesson with an external extractor and have no complaints. I have two Sig 1911s and I love them. I have never had any extraction issues. Zilch Zero Nada.
The grip screws are torx. They use the Series 80 firing pin block. The top profile on a Sig 1911 is more square than a traditional 1911, making the slide a little heftier. (They have a line of round-top 1911s for the purists)
Other than that, everything is pretty much standard 1911 as far as I can tell.
Both of mine came with very tight slides.
