I cannot imagine any situation in which I would think "Man, I hate my job. I'd quit right now if it weren't for the enlightened way they do performance review and goal-setting."

Of course that's a little unfair. Maybe doing this stuff well means that employees are less likely to find themselves with nothing important to do, or something. Still, it seems like it's focusing on the wrong things.

If you want to keep good employees, surely you actually want to do things like these: Give them interesting work to do. Give them work that has actual value for the world. Pay them well. Make sure they have good tools. Give them a sense of responsibility for the company's success (which means (1) shares or options and (2) as much clarity as possible about how their work relates to the company's higher-level goals). Make sure there are opportunities for progress.

If tinkering with performance-management makes a big difference, I think that can only be because either before or after the tinkering it was catastrophically broken.