Harmony has always been designed with a trained operator in mind. And while we still believe that this is the best way to "staff" your projection needs, Harmony 3 has been significant improvements for handing a pre-made service to an untrained volunteer to run. These improvements build on other enhancements made in Harmony 2.2, 2.3 and 2.4, such as custom song ordering and remote control mode.
Harmony 3 supports Display Actions (Clear Text and Blackout) in a service. Those actions no longer have to be manual, they can be pre-programmed.
Also, there are new preferences that control the behavior of Harmony while stepping through a service. You can make sure the background is display before song lyrics and toggle the song title.