Only been using it since the EPN launch on the 1st. Only really starting to see results now. Nice results. I guess the only way is to test it out.
(I'm using PHPbay pro).
There are HUGE reporting delays with EPN right now though. ACRUs not appearing for over a week. Check the EPN forum and be careful encoding your links.
So far the site I am using it on is getting an average EPC of €7 (Or €0.70 everywhere else). Not bad.