I have no experience with Sig 1911s. Of course, lack of knowledge, experience, or general common sense has never kept me from posting before and it won't now, either.
Personally, I don't care for the Sig-profile slide or the external extractor. I know they make a traditional slide, and I know the external extractor is supposed to be gee-whiz wonderful, but there it is. There are just too many other guns out there I'd rather have and don't have yet.
The only Sig in the house is my wife's P938. It's a solid, reliable little gun. With a blocky slide and an external extractor.