Hello,
Recently I found this great feature in the Slic3r PE where you can print with multiple colors. You just set the layer on which you want to change the color and the printer pauses at that layer, and lets you change the filament.
Is there any way to implement the ETA for the color change? So I would know in how many minutes / hours the color change will occur? It would be pretty handy.
Or if there was a way to show the layer color change in the Gcode Viewer, so there wouldn't be just black layers but it would change to different color at the height of the color change.
Just a suggestion for improvement! 
Have a great day,
Adam "Mavi" K.