More a platform than an engine, Adobe® Flash® Professional is the industry standard for interactive authoring and delivery of immersive experiences that present consistently across personal computers, mobile devices, and screens of virtually any size and resolution.
The best that i have ever use. The optimization isn't a problem, thats a problem that we can fix, the best feature of Flash is the ActionScript. I think its better than using game maker softwares where you only can do the things that are there. Flash allows the developer to experiment in a 2D and pseudo 3D environment with its own programming language. No more to say, 10/10.