Comments are helpful for improvement. That being said, many shows do not use licensed judges. Technique judging is more objective than design judging. There are some techniques that are pretty universal, such as bindings should be full and stitched down at the corners; straight lines should be straight and stitch in the ditch helps that; points should not be chopped off or left dangling; seams that are suppose to match better match; it should lay flat.
You can learn a lot and improve yourself by joining a small group with critiques and reading books on jurying and judging processes.
Each judge will give opinion and sometimes they're quite different on the same quilt.
In a judged show, I've heard that all the quilts in a catagory will be viewed together and the best visually will be held over for judging. Do all the others get comments? Don't know.