The Drone controller is an Android controller that got its start through Kickstarter crowd funding in October 2013. Evolution Controllers is the company behind this slick controller.
The Drone is marketed as a controller built by gamers, for gamers. It is very nice looking and has a number of notable bonuses that many other Android controllers don't. For example, it has custom skinning available plus can be shipped in any one of a number of colors. The Drone controller also has a unique layout with buttons on the back panel, similar to the Impulse Controller, but seemingly perhaps more thoughtfully positioned.
As the Drone controller is still in a pre-order phase. There does seem to be a lot going for the Drone controller in terms of compatibility. The Evolutuion Controllers website (and the Kickstarter site) both show how the controller is compatible with a vast number of systems, including Ouya, MS Surface, Chromebooks, Android and iOS (via iCade protocol).
The Evolution Controllers website has the full details about their Drone controller, including a nice startup guide and a "hackers" guide that gives step by step instructions for disassembling the controller.