I think 199 nailed it -- every firearm has its Achilles heel.
I was suprised to hear about the failures in the SIG, but knew that trigger spring issues were one of the big troubles of the design. There's also the breach block roll pin in the stamped slides, and maybe a few others I don't know about.
The 1911 needs to be setup properly, and that usually means two things: good mags and a properly adjusted extractor. Of course, there's also the feed ramp/bbl, fit of the bbl, and a host of other issues. But the 1911 can get so screwed up because everyone and their brother builds them in their basement (literally). Imagine what would happen if Special Weapons build a SIG P226 or Glock 17.... Thankfully it seems the 1911 manufacturers are stepping up and generally putting out better products. I've heard that Colt 1911's are again some of, if not the best available.
Even the Glock has it's problem areas.
But if you don't learn about your pistol, and then ring it out, you'll never know what it will do under pressure. That, IMHO, is one of the things that IDPA is great for.