I've had leadbolt ads sitting in my game since an year.
It made $13 till now. (the game has 20,000 downloads and ~20% retention)
I run my own analytics and the difference between what leadbolt reports vs what my analytics says is way way off. (like 1:5 or 1:6)
Besides I've also figured out that CPI isn't really coming.
I wish that C2 had figured out both ads and IAPs by now in a universal included plugin that WORKS, I've probably been requesting this since 2012. Dying hope