I got one for my birthday a couple weeks ago but haven't had a chance to give it a whirl yet. To the plus side, it has nite sites, the new ones after about s/n 11,000 have the ion bond finish and it has cool factor.
Gripes would be that I still didn't get used to the grips yet. I would like them darker, so will probably change them out at some point (just personal taste), the cerakote finish ones are known to scratch, chip and flake off easy, and it overall has a "looser" fit than my other Colts (trigger rattles, grip safety rattles, a little more slide play but barrel locks up tight). However the fit, as I understand, the marines required all parts to interchange without fitting, so they can be maintained quicker and easier.
Actually though, the "blue box" production models, like I have, are the same as the Marines get. The issue ones aren't hand fit by the custom shop - the CS ones are known as the "civilian model" and cost a few hundred $ more.