Sorry i missed your second question. I would choose StageXL over PixiJS because auf the Dart language. I also use TypeScript for other project but i prefer Dart. The Dart-to-JavaScript compiler does an awesome job. It not only transpiles Dart code to JavaScript (like the TypeScript compiler does for TypeScript) but it's a real compiler with great optimization and minification. The optimizations include inlining, dead code removal, hoisting, etc. The resulting JavaScript code is not pretty to look at, but pretty damned fast at runtime.