People start looking for Adsense Alternatives when they get banned from Google AdSense. Sadly there aren't an Adsense Alternatives which we can compare to Google AdSense. All of them pay lot less if we try to compare PPC Adsense Alternatives. Affiliate programs might give you more money than AdSense would but that's only if you have a quality site which gets loads of traffic. Since AdSense is the best way to earn money online for most of webmasters its hard to find another ad network which can replace it.
Unlike AdSense you can't earn money online same way with other ad networks. You need to test and see which are would help you to earn money and which won't. If you have a site which related to books or cameras you will able to earn money from Amazon than any other PPC or affiliate program. Also you will need lot more traffic to be successful with other ad networks.
There are so many popular ad networks. you will able to hear both negative and good reviews about those. these Ad networks wouldn't work same way to everyone. Some able to earn money from one ad network and for someone else same ad network would be a total failure. Testing echo of them with your web sites is the best way to find which will help you to earn money.