My money is on the extractor...
After reading some troubleshooting tips by Mr. Tuner and co., I found that my formerly-possessed-by-satan-failure-to-feed-and-return-to-battery-POS-brand-new-kimber fed rounds as smooth as silk WITHOUT said possessed extractor. After tweaking it a bit to remove some tension, most of the feed problems vanished. After sending it to a competent smith, who builds long range bench rest rifles that shoot STUPID accurate groups from WAY too far away, the evil spirits have seemingly been exorsized from said demon kimber.
He smoothed up some of the angles on the extractor, and tweaked the tension with a tool, aside from doing some nice trigger work and a front sight installation. The once-formerly-possessed-by-satan-himself-Kimber has managed to get through about 300 rounds now with no issues using the same mags I used when it choked.
A good smith is like a good mechanic or barber. When you find one, stick with them.
Bottom line: Don't give up on the gun.
Unlike some of the other models, ie glocks, HK's, etc, you can LITERALLY make the 1911 YOURS by customizing it to YOUR liking. It may take some figuring to get it tuned up, but it CAN be tuned, and they DO run like the wind once you get em' set up nice.
MY SA 5" govt spec ran like a deer right out of the box using ANY mag and ANY ammo I put into it. That thing fired rounds that choked a USP .45, and I would absolutely stake my life on it's reliability. Granted, she's a loose gun and not as accurate as my formerly-possessed-by-the-dark-lord-Kimber, but I would carry it over the Kimber now, until the Kimber proves as reliable.