I think that on balance, the legal system is fair more times than it is not. This does not mean that the system is perfect. It is far from perfect, because too often decisions are made for the sake of expediency rather than justice. The system is also skewed against the rights of the poor. There are really two systems of justice- those for the poor and those for the rich. The rich hire lawyers, the poor get public defenders. The rich get bail, the poor go to prison because they can't pay bail. So I guess the question is not if the system is fair, but fair for whom?
The judicial system is not always fair. There are a number of examples in which people get better results in the system if they have money and worse results if they are poor.
One example of unfairness can be seen in the link below. This is the death penalty. Poor people get the death penalty more than people with enough money to hire a good lawyer. An example of this might be OJ Simpson, who surely would have been convicted if he had only been able to afford a public defender. It is also the case that people who kill white people get the death penalty more than those who kill people of other races.
Once you get beyond money, though, the system is pretty fair. It tends to return results that are generally equitable and unbiased.