Sigs have never been marketed nor have they been sold as mass market entrys. While they have done some polymer lately, with price points, the metal frame guns are for people who appreciate quality. I know many people who have 25-40k rounds through their Sigs and they are still going strong. Timex's are good watches, but they will never be a Rolex. I have M&P's and like them just fine, but they are what they are and fit a certain role, they are not the answer for I want the absolute best self defense pistol I can carry role.
This whole heavier thing borders on ridiculous. Unless you are into the LCP, I'm OK with a minimal gun group, most of the better carry guns do not weigh 12oz. Sigs, HK's, 1911's, even a fully loaded M&P is not light. I actually saw a couple of posts saying a 6906 was too heavy for CC, funny thing I carried that and two other guns on duty/plain clothes till we switched and never had a problem or felt weighed down. Carrying any of the larger guns involves a good belt and holster, big deal.
People can and should carry whatever they feel serves them best, that's fine by me, I just am tired of the inane if it's bigger than a 642 or not plastic it's wrong posts on here....and no, before anyone gets offended this is not a rebuttal of any specific post on this subject.