All I ever got was stuff like "Joe writes excellent design documents! His code is always well tested. I always want Joe on my projects!" I'd write stuff like "Amy is extremely effective at solving problems with <blah> API's, and is a great communicator. She should do a brown bag session about her experience with <blah>." The reviews were all fluff. Some people wouldn't put in any effort at all, and write one liners. Seriously, one of my reviews was "Just keep on being Joe!" Thanks, but why bother?
The review process at most companies is a big waste of time and money.