I have the GI version and it has functioned very well. There are others here that know much more about them, but the Mil-Spec version has better sights, flared and lowered ejection port, and, I think, a beveled magazine well. Could be other differences that I am not aware of. I have the 4" Champion and 5" full size in the GI spec. and both can shoot better than I can. This was my first 1911 size, also. Have never owned any other brands so have nothing to compare them with. You should get some definite opinions here, though. Have fun with whatever you decide.