I have a Colt 1991A1 Compact and a RIA M1911A1 G.I. both in .45 ACP (that's the only caliber besides a .38 super that should be in a 1911 IMO)
The Colt is mainly for CCW and the RIA is more of a range/HD gun, although I have carried it concealed a couple of times. Ammo is the same and if i need to use that larger mags from the RIA in the Colt, no prob.
I like to build a defensive handgun battery where the operating controls are similar and easy to transfer from one gun to the next, vice having a 1911, beretta 92, p7, etc.