My guess is that development on the new HTML editor began before CKeditor was available... not to mention, as I can tell from experience of using, the CKeditor is integrated a slightly different way especially with the file browser (something that is not as friendly with licensing). But I do know that the HTML editor will have a fairly comprehensive file browser with the ability to edit images including crop them right within the file browser.
So far, the documentation says the latest version if FCKeditor. So it will probably be 2.6.5 or, at least, 2.6.4. The other thing I noticed was SecurityAssist integration which I hope means that the file browser can easily be protected with rules based on SA's rule manager.