I'm an Airpush representative. Some answers to your questions:
1) It is a fact that Airpush developers earn 10x - 30x higher than traditional in-app ads. This is why the platform is growing extremely fast with over 10,000 live apps and adding 100+ per day. We recently gave some growth statistics and charts in this interview with Android Authority. We also post the previous day's CPM and fill rate on our website so you can see the actual data.
2) Airpush is absolutely not adware or malware -- it is simply an alternative form of mobile advertising. A permanent opt-out link is tagged on each and every ad, and users can easily uninstall the application display Airpush ads. To determine which application shows Airpush ads, the user can simply check his Recent Apps by holding the Home button, and also the application name is displayed post-click in the upper left of the Webview container. Also, Google plans to include capability for multiple click events within items in the notification tray, at which point we will be able to have a 1 click opt-out versus the current 2 click process. Still, it's a very simple process to optout today, which isn't something any other networks offer.
3) To our knowledge, we are not the only CPM-based (ie; paid for impressions) mobile ad network. Some traditional mobile ad networks like Mobfox have a CPM product, where you get paid for impressions rather than CPC-based.
4) Regarding getting banned for using Airpush -- we have over 10,000 live Android apps using the Airpush SDK. There was only 1 developer who got temporarily suspended (APNDroid), and he was immediately unsuspended within 24 hours. His temporary suspension was due to an incorrect installation of the Airpush SDK which caused his app to crash.