Assuming that this force is competent, it could be a good bit of PR for the United States, as it would show the world that with U.S help, the Iraqis are capable of managing the insurgency by themselves. However, there have been several criticisms raised about the oversight of the special forces themselves. According to the article, the UN inspector general cites weak oversight of the special forces and lack of funding by the Iraqi government. There is also worry that since the forces are under the command of Nouri-al-Maliki, that they could be used as an extralegal force to deal with political opponents, as has been alleged with the crackdown of protests in reaction to Middle Eastern unrest.
The U.S. can't really do much in this situation. If we insist on some type of oversight role, it would run counter to our commitment to leave Iraq. On the other hand, if we do nothing and Maliki ends up using special forces as his own private goon squad, it's on our hands. Part of me just wonders if this training is going to bite us in the ass. The same sort of thing could be said about how we armed the Mujahideen in Afghanistan to fight the Soviets. Yes, arming them accomplished their intended purpose of repelling the Soviets, but it also led to better armed insurgents during our intervention.
Obviously we can't determine what kind of blowback, if any, will come out of training these special forces. If it works out, we've helped strengthen Iraq's government and provided a means of which they can preserve stability. If it doesn't, we've helped arm secret police. Regardless of the outcome, this force is something the U.S, should keep an eye on.