I've just used the new PPR system for the first time and must say I think it's a pain
The problem isn't that they want PPR on incomings, and a proper book out on outgoings: I can understand that. It's the web based method that I dislike.
Mostly, I imagine it will work OK; but, as opposed to the systems at other similar airports where you call up and speak to a human being, the email acknowledgement you get tells you that you should normally receive an acceptance or rejection in half an hour but, if it takes longer than 2 hours to see one of their FAQs. That means you can't rely on flying in or out at short notice.
Frankly, I think it's an over-complicated and clunky system that should be re-thought.