I paid for EstlCAM and never looked back, really. I use Fusion360, but have never even attempted to use it for CAM. Perhaps not a helpful answer…
The only limitation I have found with Estlcam is that it sometimes forgets to take into account the other side of the tool and can try to cut into the work on the side of the bit opposite of where it is calculating the path, when the other line is a different path than the one you are calculating. I have only run into this maybe twice, and made adjustments to my drawing to compensate for the issue.