I have only ever gone for adsense and adbright i would say adsense is the best by far but adbrite would be the next one down in my opinion.
Adsense is not that hard to get excepted for if you have good unique content,no adult content,hacks,pirate content.
I have made blogs within a few hours and got excepted for adsense sometimes it can take a few days for them to review it. Adsense does not like sites under construction this has got me rejected in the past. Its best to wait untill its finished and get a good few pages busting with fresh juicy content.