I previously used Cura and found I needed an extrusion multiplier of 1.14 to print correctly. I am using a bowden extruder with a .4mm nozzle printing 910 alloy nylon. Reason I'm using s3d over cura for this print is because s3d actually does combing properly.
In S3D I need 1.27 to get decent results. Any higher and it seems the outer edges of the print suffer.
The extrusion seems to be hit or miss. The outside edges sometimes rotate between being thicker and thinner from layer to layer and you notice this easily. When printing top layers sometimes there are gaps.
Also some spots of the filament almost look like they would if the filament was wet (slightly clearer and white in places), however I dry my nylon in an oven. If I do a back to back print cura doesn't do this.