In my personal experience some of the product owners do not know how to prepare their landing pages, so they hind it hard to earn from selling their product with PPC platforms. If you ask, for example @coolice, he will tell you. Before starting any kind of PPC, we carefully create and test the landing page. There is no other option, if you want maximum results for the money you spend on sponsored ads.
In the last few years more and more affiliate programs pay attention on landing pages and the whole promotional package. Banners, videos, text links, content, and more. Landing pages were the latest thing, they were thinking of. Not all affiliate programs, of course.
I still believe that an advanced webmaster could build up better landing page. Why I focus your attention here? Because your landing page is the main tool and sales generator of the whole campaign.