there is so much crap on click bank that I would always suggest that if you are going to promote any products from clickbank that you purchase the product 1st so you know what you are promoting, but buy it through your own affiliate link so you get it half price
If I could sum it up in a few words, I would say it like this. Clickbank is a virtual whoring system.
Clickbank is a great platform for people looking to start making money online. It doesn't cost anything to get started as an affiliate, and eventually you can become a vendor and have affiliates selling your product for you.