From the Google perspective, you are welcome to use both YPN and AdSense on your site. However, you cannot place both YPN and AdSense ads on the same page as this would violate the 'Competitive Ads and Services' policy.
Great, Im just testing waters Adsenseadvisor! But so far the result are not very good so Im sticking with google :) Gosh google is always the best on everything! well maybe we need some more support :)
Google is the worst on everything over here, including support. All but a few sites have been switched to YPN. The google search box has been left on a few pages, but that is just pennies per day. As soon as each site hits a dumb pricing trough I switch it over to YPN, and every time ecpm and earnings have sky-rocketed.