For what it's worth, I guess you could classify me as a Rock Island Disciple. I have 3. When I decided to look for a Commander-sized model, the RIA comes as a 4" with a bull barrel. I wanted a 4 1/4" with a bushing and started to research. Since I obviously have no problems with Phillipine 1911s, I gave a hard look to both the American Classic and the ATI. The ATI was about $50 cheaper, and had the stock GI accoutrements. It also had a parkerized finish. Their CS didn't seem to be to the level of the RIAs.
The American Classic, however has a beautiful blued finish, BTGS, Skeleton Hammer, Trigger, Checkered Grips, Novak Sights, extended Thumb Safety, extended Slide Stop and a great CS reputation. I now have the AC Commander and so does my dad, he liked the feel of mine that much. He bought his before we had a chance to shoot mine.