Another feature of Molehill is that it chooses whether to use OpenGL or DirectX or fall back to software rendering if neither is available. That's not to say it's a magic bullet. If you post more details of the specific project, you will probably get more qualified feedback. For example if you're targeting iPhone and iPad only, then there might be better alternatives. The other thing is, who is going to develope the application? If your used to programming OpenGL, using Flash will be like doing keyhole surgery.
Oh, and a last point, you might want to put that question on other forums, we tend to be quite biased towards Flash here :)
