Kontera - 8:21 am on Sep 24, 2012 (gmt 0)
This is Jonathan from Kontera. Empty Room, Kontera generally performs better thanks to our Content Activation Platform which delivers more relevant ads and because of our exclusive ads inventory from some of the biggest brands in the world.
However, and this speaks to ember's point, because our ads are geo-targeted, it will depend on if your content is in a topic our advertisers are targeting, and if your readers are in regions our advertisers are targeting, if you experience the same level of differentiation most publishers see.
Regarding load speed, that's not an issue with Kontera, as by default Kontera is the last element of a page to load.