The problem exemplified in the top comment was perfectly demonstrated by my control theory classes, where we ended up with a dramatically distorted view of how you actually use the damn thing because they didn't teach us PID at all. It was treated as a special case that was trivial to analyse given the other techniques they wanted to teach us, so it got no airtime.
1. PID's work adequately for more situations than anything else.
2. If a PID doesn't work you should redesign your hardware.
3. Phase noise will totally mess with you.