I don't know much about HaxeFlixel. In a general way, the approach we took for the Superpowers Game engine is similar to Unity's: you work with actors (game objects) and components. I'd say the workflow is simpler and lighterweight though, as the scene editor isn't the be-all and end-all. Instead, each asset has its own editor and you can easily work with multiple scenes at once. The scripting experience is great with autocompletion, live error reporting, a built-in API browser, and debugging is very nicely powered by Chrome's dev tools. Any specific points you'd like to know about?