Understanding how Web Parts are rendered, why to never use Render() and a bit on accessibility

Great post by Andrew Connell...

When building custom Web Parts, you always hear people say "don't use Render(), only use RenderContents() or use the more OO approach and implement CreateChildControls()." Personally I favor the latter approach of using CreateChildControls(). So why should you not use Render()? Because unbeknownst to you, you are actually breaking something quite powerful.

Check out the full post here.