WebGL-2D should be faster than Canvas2D at certain things and slower at others.
It is important that you know what to expect when using WebGL-2D with your
project.

This directory contains benchmarks for testing performance

asteroidsbench/

  Kevin Roast has graciously given permission to include this benchmark in the
  WebGL-2D project.

  This benchmark is perfect for testing real world canvas usage in game engine.
  It relies heavily on 9 arg drawImage cropping to implement scrolling
  backgrounds and stripstrip animations.

  Visit his website http://www.kevs3d.co.uk/ for other HTML5 canvas demos as
  well as the asteroids game http://www.kevs3d.co.uk/dev/asteroids/

  Twitter @kevinroast http://twitter.com/kevinroast

  Copyright (c) 2011  All Rights Reserved - Kevin Roast http://www.kevs3d.co.uk/