Are there any built-in html formatters in the editor or do I have to implement one myself? The html produced by the editor is all lumped together and it's hard to match the open and close tags.
Yes, RadEditor offers a client-side HTML indentation filter, which displays nicely indented code in HTML mode. This way it is much easier to read and modify HTML content. You can see the attached screenshot for more information.
The HTML Indentation filter is enabled by default and it indents the content in a very similar to VS2005 way.
Please, test the filter with sample HTML content and see whether the same content is better indented in Visual Studio.