The success of Android does not surprise me. The programming is very simple. The development tools are really comfortable to use. I think Android will also make its way in user interfaces in the industrial context.
For tablet and smartphone application, Android might have advantage over others since the success of these products are heavily relying on the marketplace. Ubuntu, no doubt, will get some attention. In typical embedded application, memory footprint becomes very critical. The lesser the memory; the better popularity. For this reason, FreeRTOS gets a lot of attention. Commercial OS will likely be around for a while. Defense industry uses might be one of the many primary reason. I am very interested in learning the breakdown of various OS to industries/ applicatons.