Crossfit is a civilian invention. It's founder, Greg Glassman, was a gymnast before anything else.
The stated goal of Crossfit is increase your General Physical Preparedness (GPP). The term GPP is just Crossfit jargon for "competent in all areas of fitness" or simply just "In good all around shape". They break it down into 10 areas of fitness, but really, for the layman, that's all it is.
Being a marathon runner does a firefighter no good if he can't carry someone out of a burning building. The cop with the biggest muscles is useless if he can't run down a criminal over two city blocks. In the military, we prepare for the unknown, and our what we consider to be "fit" needs to reflect that. The "anti-specialization" philosophy is what makes Crossfit attractive to soldiers and emergency services.
But consider some of the offshoots of Crossfit: www.crossfitendurance.com and www.crossfitfootball.com. These sites were started by people who liked the Crossfit method, but see the need for some specialization in order to compete at specific sports. Marathon runners want a brand of Crossfit that emphasizes the endurance aspect and football players want a brand of Crossfit that would build more mass. Crossfit might be ideal for someone who just wants to be in good general shape, but those with sport specific goals require sport specific training. Even some of the most famous Crossfitters like Josh Everett supplement Crossfit with training specific to their chosen sport. In his case, it's Olympic lifting.
Enter Rob Shaul and his website www.militaryathlete.com. I was first turned on to militaryathlete by biosci in the "Crossfit and the CF" thread here on army.ca. Looking into it I think it's superior to Crossfit for our uses. Why? Because it's Crossfit tailored to army guys. Ruck marching is built right into the program. There is a heavy emphasis on durability training. The more technical Crossfit exercises like double-unders and handstand pushups fall to the side and more emphasis is put on strength building barbell exercises. It's like sport specific training, only the sport is deployment.
I've seen Crossfit used as PT at the unit level for extended periods (months) with ruck marching worked in based on a common sense approach. In my opinion, it worked well, but I still think militaryathlete wins based on the physiotherapy exercises regularly used in the program. As well, If you read the Q&A emails Rob Shaul posts on the website, you really see that he's a man on a mission. Unlike the personalities found in mainstream Crossfit, Mr Shaul comes off as a really humble guy who's just looking to support the troops in the best way he knows how. He's open minded in his training theories, and he's quick to point out that not everything works for everyone.
I highly recommend militaryathlete.com