Springfield has created a lot of confusion with their product names, because the "Mil-Spec" ... isn't.
The Auto-Ordnance 1911 is a close copy of the WW2 M1911A1. Springfield also makes such a pistol, but it's the GI, not the Mil-Spec. A-O's is actually the closer clone, because the Springfield uses non-authentic grip panels, and has the lock in the mainspring housing. These two guns are roughly competitive in price, but since around the end of last year the A-O typically has been selling for around $50 less than the Springfield. The Springfields are made in Brazil, and the rate of exchange has gotten worse, so this is not really something that Springfield can control.
The Springfield Mil-Spec is superficially similar to the GI, but it includes some improvements such as lowered and flared ejection port and better (easier to see, but non-authentic) sights. It costs more than the GI. I doubt anyone has seen Mil-Specs in the $400 range. More than a year ago (before the prices went up) a friend of mine paid $419 for a Springfield GI. These days, you're not going to find a new one for less than $450 or $500. In general, the A-Os will be less expensive and are closer to the authentic configuration ... if that's important to you.
Quality consistency is probably better with Springfield. I know of people with excellent A-Os, but I handled a new one in a gun shop on which the thumb safety was extremely safe -- once applied, it could not be disengaged. The one next to it on the shelf appeared to function perfectly, although it felt a bit "gritty" to operate.