According to someone they are a plague of contemporary internet and according to another they are a classic business tool. How to approach them is highly debatable. But one is some PR articles they really work.
They will really help you improve your search engine rankings along with the praSEO technology to ensure that your site is shown high even if it doesn't get there. It is only necessary to have good PR articles and find an agency that will make the Internet more original than it will include you with the warranty and quality crap for your business.
Reliable PR articles really help but only until the competition is paid for by similar services then the fight in which individual companies beat themselves on the Internet starts.