Share as much or as little as you would like, in good reason. Do not share any biased opinions about the student. Stick to the facts. You can say "I enjoy having them in class" or "They are so helpful" but try not to focus on things like, "They won't stop talking" or "They are really behind". Always have a plan for what you are going to say, and bring notes of data if you need it to support your statements.

You do not need to go into detail about anything you do not want to. I think going over their work and showing the parents the amount of effort they are putting in is important. If the student is having troubles, do not be afraid to express your concerns.