Forum Moderators: martinibuster
I want to get a fair idea of who I should consider and if their cost per click is similar to Google.
Is it possible that PSA's are appearing as a result of stop words or phrases, or maybe the page is a dynamic one and adsense has problems with these sometimes. Have you specified image ads only? Lack of inventory is unlikely to be the problem.
I'm also from the UK. I use Fastclick as alternate ads on occasions, but lately I've taken to not specifying an alternate ad at all.
Alternate ads replace adsense so both aren't actually shown on the same page at the same time. Therefore whatever you choose to be the alternate ad is going to be fine by Google. Maybe if they don't look or feel like Google ads is possibly a good thing - reduces ad blindness.
I have alternate ads for many of my ad units. I have created ad units with little images and direct product links that point to my Amazon Associate account. I also use the collapsing ad unit feature for some of my banners which works really nicely.