Is there a reason you're only interested in iOS?

We do Android apps only and have completely been focusing on free apps in the Google Play market with in-app ads. Our own systems evolved into an SDK that anyone can use now and we just announced standard format banner-ads that tie in nicely with Admob mediation today: http://news.ycombinator.com/item?id=4295631

We're 4 people at the moment working only on our own projects and we're in the process of hiring more engineers.