Which Intext Advertisement Company is the best?

Hi guys, this is my first message. I am wondering which company is better for intext advertisement.
Rubicon, Kontera, Infolinks, meebo, Pubmatic, Chikita
My visitors are mostly from middle east. But i have some websites for US also. Right now i got 4k-5k adsense impressions everyday. Its a forum. adsense gives like 3-5 cents for each click and 10-15 sent for each thousand impressions.
I know i have more income potential from this site. Can you give me some advices?
PS: Limitations for the new members are pretty annoying.

See original post by Website_Playboy