I'm seeing better targeting too, and EPC has been remarkably consistent since I joined YPN in early Sept. AdSense, on the other hand, has dropped the ball (at least on my sites). Their targeting has sucked this entire month, and my CTR and earnings reflect it. I'm considering a move of some 6,000 pages from AS to YPN. Gonna give it a bit more time to see if AS shakes out their targeting bug.
Overall, I'm very happy with YPN! Their EPC blows AdSense's away. The only negative (and it's to be expected with a new service) is hit-or-miss targeting and low ad inventory. Once Yahoo! gets those areas squared away, and assuming EPC doesn't tank (big assumption, I know), I'll run from AdSense like a looter from the cops after a hurricane. :-)