The only differences that I've perceived is that Kimber's fit and finish is a little better than Springfield's, but its my understanding that Kimber uses a lot more MIM parts while more parts on the Springfields are hand-fitted. MIM parts are about as good as milled parts if done right, if done wrong, they tend to break easily, Kimber's MIM parts fall into the former category. Springfields do use MIM parts as well.

The passive safeties on the two pistols differ greatly as well. The Springfield uses a lightweight titanium firing pin to prevent it from firing if dropped, the Kimber uses a Schwartz safety similar to that used in Colt Series-80 pistols. The Schwartz safety adds unnessary mechanical complexity to the pistol, there have been some issues with failures caused by the safety, though they are few and far between. Interestingly enough, Kimber left the Schwartz safety out of their Desert Warrior pistol, which might be one of the best 1911s that they make.

I've had one of these for about 4 years now, only complaint that I have is that the slide serrations are cut too sharp- they eat up your fingers and eat up holsters, but from the pictures on their website, it looks like they might have toned them down a bit. Other than that its been an absolutely flawless and accurate shooter for thousands of rounds- I've shot everything from jacketed hollowpoints to cast lead loads through it with no problems.