I have a SIG RCS and it has worked flawlessly through thousands of rounds. I have no problem with the external extractor design as all I care about is whether the gun works or not - the one I have is totally reliable and has never had a stoppage.
I too have a Sig RCS .45 ACP, as well a pair of Ruger SR1911's, a Colt Gold Cup, a Series 70 vintage Colt Combat Commander, and 4 other Colt Gov't Model 1911's...you could say I love 1911's and not be far off.
I was given the Sig by my #2 son as a Christmas gift, liked its looks, 'melted' surface treatment for ease of presentation in CC use and its accuracy...comparable to any of my semi-tricked out and thoroughly gunsmithed Colts. Unfortunately, it had feeding problems...rounds, even hard ball, round nose types, would hang up on the mag/frame feed ramp junction.
I called Sig, had no problem getting through to them, and found their CS rep. thoroughly knowledgeable about the gun. He sent me a FEDEX shipping label and promised a quick resolution of the problem. I had the gun back in less than two weeks with a new barrel, and a trigger/action job that has to be experienced to be believed. It's been 100% reliable since and accuracy is less than 2" at 25 yds from a rest...as good as any of my Colts.
It's a wonderful carry piece, equally good on the range, and when I'm toting a mostly full size auto, my concealed carry choice. It's light weight, melted contour, flared mag well, checkered back and fore grip, Novak sights and match grade accuracy make it a great gun.
I can't comment on the rest of Sig's 1911's but this RCS is first rate in every regard. Pic added. Shows Ruger's CMD and Sig's RCS, Rod