I've been doing well with affiliate sites geared towards CPA and Adsense offers, and haven't delved into Amazon much.
A couple of months ago I decided to tinker around with an Amazon affiliate site and set up a simple review-style site for an electronic niche. The market and keywords are EXTREMELY competitive and after some serious SEO work still not leading me into the top 3 pages, I pretty much forgot about it and focused back on developing my CPA and Adsense sites. As it sat, the site only had 5 pages and 2 posts.
Fast forward 6 weeks later to today:
I got an email from Amazon stating that they were trying to pay me money owed but my payment info hadn't been filled in.
"Sweet!" I thought, maybe I got a couple buys randomly. Good times.
When I went to check however, I had earned $117.12 from my forgotten site from a total of 21 sales! 19 of the 21 sales were somewhat related to my product niche.
It just goes to show you, Amazon DOES convert well, even with a half-hearted effort on a review site. I'm just imagining what I can do with more posts and a bit more effort; I'll be sure to look more into Amazon sites now.