From the Washington Post:

Today, there is one camouflage pattern just for Marines in the desert. There is another just for Navy personnel in the desert. The Army has its own “universal” camouflage pattern, which is designed to work anywhere. It also has another one just for Afghanistan, where the first one doesn’t work.

Even the Air Force has its own unique camouflage, used in a new Airman Battle Uniform. But it has flaws. So in Afghanistan, airmen are told not to wear it in battle.

One of the reasons that the services may elect to have different uniforms is that it helps with branding. When Congressional delegations (CODELs) visit, it is important for each service to showcase its contributions as this may translate into higher appropriations.