I would very much agree with the summary of the article by Susan Heathfield on the Pros and Cons of 360 Degree Feedback.
As someone who has developed very specific 360 Degree Feedback models to support appraisal, training and leadership development, I would say that the failure to connect the 360 Degree Feedback with what's going on in the rest of the company is one of the major challenges when trying to get the best out of 360 Degree Feedback.
You can't run 360 Degree Feedback in isolation from the major activities in the organisation, the big goals and values, and other stuff that's going on to improve performance.
Get it right from the start, and it will be a huge asset to your organisation!