I have tried Eagle & pcb-gcode following example athttp://www.instructables.com/id/Turn-your-EAGLE-schematic-into-a-PCB/
I have generated the G-code and have a look to the result given by pcb-gcode and i can see problems with the toolpath generation:
there are some shortcuts !!
You can have a look to the joined files: i put a screen copy of the settings in pcg-gcode (it runs under eagle) and the result.
If somebody have some hints, they are welcomed !