This is a great question. I am completely in favor of privatizing prisons. There are many reasons for this.
First, we all know that something has to be done with prisons as it stands now. They are not run well and they cost too much money.
Second, in almost all fields, if not all fields, a private company does better than the government. The government is ineffective and not cost effective. When there is no ownership, there is little incentive to do well. People put in enough, but nothing extra. A private company is different, because it is very much about profits and being effective - after all, it is a business. Moreover, there are real incentives. For these reasons, a private company would do a better job.
In a study that took place in 2008, research showed that the government saved about $15 million dollars yearly when they used a hybrid model of private and state prisons. The study was conducted by the Vanderbilt Institute of Public Studies.