I am not sure which version of RadEditor you are using, but neighter one of RadEditor builds does not expose any limitations for rendering the content inside it and outside it. The content area of RadEditor is a standard editable iframe or div, which is a browser's HTML element and the content rendered in the editor should be rendered in the same way when it is rendered outside of the control. The problem is most likely related to some global CSS styles for TABLE or TD elements, which resides on the page and breaks the content appearance of the tables.
This is a developers task, but if you would like you can examine with IE developer toolbar or Firebug, how the content is rendered in RadEditor and after that in the page and compare them. Check for global CSS styles and see whether they are not causing the problem.
If you can, provide a live url to the problematic page so that I can examine it on my end. I will be also able to see which version of RadEditor you are using.
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