I cut out some ellipses from 1/2 King Starboard. It was jigged on a vacuum table on a PRT 120 with a 3.5 hp (I think) Columbo. I tried various cutters, feed speeds, spindle rpms, and z axis step levels, but none gave edge quality as good as hand routing. At best, you could see little tiny serrations on the edge of the ellipse.
I put my hand on the y carriage to see if I could feel some jumping and I did. Not visible with the eye, but you could feel the jumping, I guess that translates to the part. Is there a way to get a smooth cut on this machine? The vibrating more apparent at the smaller ends of the ellipse.
If you cut the ellipse out of wood, I don't know if it would be as visible, but I imagine plastics will show it more.
john@mindsightdesign.com