The thing is that most people build their PBN's in a way that it is only a matter of time before they get taken down. I read something earlier on BHW about someone saying that a PBN is a churn and burn method, albeit one with less risk. Are you serious?
Build your sites in a way that you know 100% will pass a manual review. This includes the biggies like no massive footprints, but also the little things like adding a Twitter and Facebook page, a custom header, contact and privacy policy pages etc., don't have all your links going to your money site on your homepage either.
If if a competitor tries to get your network taken down, he won't be able to (and probably won't even realise it's a network site anyway). He's trying to take down a real looking site that doesn't have bullshit content like "Top 5 Juicer Reviews" on its homepage that only links out to your 5 bullshit juicer reviews. How many big websites do you know that even link out on their homepage? Inner page linking is underrated.
A site used in a PBN should be indistinguishable from any other real site on the net. If you're spending both time and money in creating a PBN you may as well do it right.