I kinda like what my employer does. There is a 1-5 ranking, but the distribution/buckets for bonus is determined after the reviews are complete. Of course, the concern here is that management "can" slot the buckets in a way that suits them, but I trust them enough to not do that.. Due to this, no one knows "what needs to happen to get X bonus".. everyone is just trying to do their best to get to the highest score and the amount of cash you get depends on what bucket you fall under