No they do not pay as much overall, but some there are rare cases where people have found that they pay more.
Sure why not. "if" you can get accepted you can try for yourself. These questions really only apply on a case by case basis. Yes Google is a better program, and yes you can make money with YPN. Who pays more? Depends on who you are and what your site is about.
They used to. Not sure about now, it dosent even look like their accepting many people into their network at the moment.
If you have the same content and budget and everything starts out equal then Google should have to be the pick for your money.