some say they are worth only for the do follow, anchor text that you get to your deep pages! G seems to like branded sites and one way to tell G that you are a brand is by doing paid Press realeases! That is what i think! Keen to know what others think. I have got some results with free ones as well & wondering whether i shd go dwon the paid route too - so as to get proper anchor texts!
PR is one of the best ways to get your traffic. Search on Google on some competetive keywords and you can see PR site can occupy the 1st page of Google.