COLT vs Springfield 1911's ??
In my opinion --- price, mostly. I like Colts because I am a traditionalist when it comes to firearms. I stick with the basics and try to get good with the tools I use.
I assume you are talking about commercial, Government Models, not GI, 1911/1911A1's, .... soooooo ....
The commercial Colts of this design are known as Government models. In 1929, Colt introduced the Government pistol in a new chambering, the .38 Super Automatic, a "hotter" version of the earlier .38 Automatic cartridge. New pistol had bigger magazine capacity (9 rounds vs 7 rounds for .45 ACP) and sold well on the police market. The .38 Super versions are still manufactured and used mostly as competition guns due to extreme accuracy (and extreme-er cost).
During 1970 - 1983, Colt manufactured Mk.IV series 70 Government model pistols, which closely resembled the original M1911A1s, but with accurized barrel bushings. Since 1983, Colt manufactured Mk.IV Series 80 Government model pistols that featured an added firing pin safety --- making the trigger pull not to my liking, but they did not ask me. The latest Colt commercial product, the M1991A1, also featured Series 80 slide with firing pin safety. The Colt has the Series 80 firing pin safety and the Springfield uses an ILS (integrated locking system) which is located in the mainspring housing.
The Springfield's major parts are made in Brazil from castings; unless that has changed in the past year. Colt used to be milled, but now, most are CNC made. The Springfield also has a little thicker dust cover and front strap than the Colt --- you can tell the difference in feel. It uses a .38 Super firing pin, which was changed to make the pistol more California drop test-friendly.
This comparison is incomplete --- you could write books on the subject of the 1911 and clone differences, and many have .... but not to worry. Either one will give you excellent service if you do your part.