I work for a large manufacturing firm and we decided to try 3D printing for prototyping, jigs, fixtures, and various gripper fingers before sending to fabricators to get metal ones made. So far we have had great results and saved some money by finding design flaws or easily making modifications that are easily noticed using our models.
One of the very first prints I did was of a race bearing assembly to just test the capabilities of the printer. I am happy to report it printed very well bearing and all and after some trimming it works like you would expect a bearing to work.