Best Ad Network?

We are going to start implementing ads for our game soon, and wanted to hear people’s experiences with the supported ad networks in Corona:

AdMob, AdMob-v2, iAds, InMobi — basic, InMobi — enhanced, inneractive, Vungle, CrossInstall.

For reference our game is:

http://www.yosuatreegames.com/evubble-coming-soon.html

Gameplay:

https://gfycat.com/BlankMassiveHawk

We want players to be able to earn stars(an in-game currency for upgrades) by voluntarily watching video ads. Any recommendations?

Thanks!