There is an article at gamasutra about Flash vs. Unity for the future of web 3d games. But it really is the future of true, hardware accelerated gaming, applications and interactives, not just 3d but massive, immersive 2d+3d works/projects on the web and available via browser.
Adobe, or Macromedia previously, owned 3d games with Director (8.5 with Shockwave3d) for a time, but that was really before mainstream was ready (2000-2001-ish). There was a lack of computers with dedicated video cards and GPUs. Today, even the bottom line computers have a decent video card. Also, the surge in mobile and the need for native level access to graphics hardware has spawned this new battle (Thanks Apple!).
Unity has the pipeline, 3d and has been doing that well since 2005/6. They emerged from Director and even have some members of the Director team working at Unity. Adobe is just getting back into this, they dropped Director (or left it wavering) and are now going to attack on the Flash level not just against Unity but to hardware accelerate it for mobile and better video playback hopefully (they currently hardware accelerate scaled video to full screen).
Like the Silverlight vs. Flash product competition, Unity vs. Flash is actually a good thing for developers and both platforms. With Torque3d wavering, html5 and WebGL more than a year out (and WebGL maybe 2-3) for broad mainstream support (I am looking at you IE), this is the time for Flash to move on this and Unity to keep going they way they have. Hardware acceleration makes these plugins relevant and ahead of the current standards emerging in html5 and WebGL.
I love using both tools and they have come a long way since painful Director lingo/w3d/plugin hell for hardware accelerated gaming, apps and interactives. The gaming industry and web are merging, these two products should get a good portion of that projected $87-billion total game market’s annual revenue in five years, as investment advisor Digi-Capital predicts.
It is also a great time to be a developer having these companies vie for developer support. It is exciting that hardware acceleration, 3d games, and widening game industry are all emerging and will be a big thing for the next few years at a minimum.
It is finally time to kick it up a notch. Game on!