foofi, I strongly disagree that reports are between parents and teachers. You can discuss reports and praise children without comparing them.
At primary school my children all asked to read their reports and I could see no reason why not. At secondary school, the children get the reports first, and have to write citizenship statements on them. They also have regular target-setting reviews with teachers.
Our children get grades for both attainment and effort 3 times a year, and once a year it's the full report with written comments too. We praise good results for attainment, progress and effort, and are careful to praise for that particular child and not for the actual grade - one child might get say a level 6 with their eyes shut, while for another child it might be a real achievement.
We don't reward with money, possessions or treats, I don't think that's necessary.
I think all children are savvy enough to see through comments that aren't sincere or are too general and not specific for that child. Mine certainly are, and we've had some laughs over some comments.