I tried to join up a small PR1 site that posts short stories/news along with relevant back links. Signup appeared easy and simple, but although I tried and tried, the interface stuck on "submit" when I tried to run up my first story. The delay is so long, I could have installed a wordpress website on one of my better hosts by now and posted my link there. hmmmm...
Conclusion? None yet, but it appears I could do worse trying to get a link on an uncooperative site than just building a subdomain that focuses on the same topic, create better or equally relevant content and take the link from there.