Kickedout - 4:22 pm on Jun 13, 2012 (gmt 0)
I test only one week (2 or 3 weeks seems a lot of time) and compare RPM to past week. I really don't see much difference, already tested the 3 options. Images only works for some sites but I'm seeing lots of "Adwords" banners on my sites, so guess that means there's not enough publishers. Personally I find a lot easier when I use adwords to creat Text ads instead graphical campaigns.
I like the images better than text ads (the appearance I mean).