When it comes to montezing apps or games whether they are HTML5 or Native Android/iOS apps, Lead Bolt is the solution for you. It is very easy to use compared to Admob. With Admob, you have to do some SDK stuff just to put ads in your apps or Games, but Lead Bolt has a simple no headache HTML script you can copy and paste into your HTML5 app or Game. I just finished inserting my Ad Code into an upcoming Game and Job Search app.
You should really consider using LeadBolt and best of all you can sign in with your Google account without registering for a separate Lead Bolt account.
Another thing that I dislike about Admob is that it forces publishers to stop using current Admob system in place for a new updated one. This is annoying because developers have to login and update their apps or games with new Ad system.
Lead Bolt has wide variety of ads such as banners that stretch and other ad types.