I got nice quality on Chrome 21. Substitute the window.requestAnimationFrame directive with:
window.requestAnimationFrame = (function() {
return window.requestAnimationFrame || window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame || window.oRequestAnimationFrame ||
window.msRequestAnimationFrame || function(callback) { window.setTimeout(callback, 1000 / 60); };
})();