Excelent Ad network with good user engagement idea

When they contacted first, I was bit reluctant as we used to get many unwanted ads from many people. After couple e-mail interactions I agreed to keep their ads for one month and after I never felt removing their ads from my site. I using them for almost 10 months now. They are very helpful people and they are just an e-mail away. Thanks guys for quick support which I got from you. Last but not least their prompt payment.