Well, my chartboost experience money wise has been quite OK in relation to my ad revenue, which generally sucks big time. Mostly because the games have few if any long term installs/players. Don't know why you have poor results if you get lots of players though. But if it gives incentive to pay to remove ads, it does the job, right?
But yeah, more diverse ad network support would be nice. I also posted earlier a lengthy post on how banner ads on AdMob are broken in AppGameKit as well. Nothing happened there either I guess. Nor do I have any idea about mediation still etc. Pfff