360 degree appraisals are a powerful developmental method and quite different to traditional manager-subordinate appraisals (which fulfil different purposes).

Some people advocate separating appraisals from pay review, however this does not make sense in organizations which require staff to be focused on their contribution to organizational performance, especially where there are clear accountabilities and measures.

Performance appraisals are essential for the effective management and evaluation of staff.

Be as truthful as you can without exposing yourself unnecessarily. Obviously if your company and/or boss does not have a positive and fair approach be careful not to create vulnerabilities for yourself.