In any discussion of Flash performance, usually someone posts a report of their CPU fan spinning up each time a web page with Flash is running, or a performance

In any discussion of Flash performance, usually someone posts a report of their CPU fan spinning up each time a web page with Flash is running, or a performance meter getting pegged, or the computer's performance notably degrading. So there's reason to suspect that mobile Flash will suck more battery than a native app. It's possible that Flash's movie clip-based object model encourages a "polling" approach to interaction over an event-driven approach, making it harder for the CPU to sleep.