LivePerformer! seeks to fill a gap in the music software landscape.
It is aimed at the performing musician only.
It lets you use VST plugins on stage easily.

You can use it to play virtual instruments (e.g. with your MIDI keyboard or any other device that sends MIDI notes),
to use audio effects, and to have live control over your audio routing.

The basic idea on how to use it on stage is very similar to the above video.