I use this Combinator patch at the end of my audio signal chain and is the last chance to tweak my sound before I bounce a mix. With it I can visualize the audio hitting the audio outs, can tweak the EQ via a graphic equalizer and add some warmth to the sound. Thanks to Robbneu and his excellent Reason Patch a Day blog for providing the basis for the EQ / Visualizer using BV512 effects units (in his fourth post, way back in September 2008!). All I did was add a Scream patch and provide a custom backdrop.
In case you're wondering, button 4 simply gives visual feedback that your track is "Done!"