The good thing about Hallo is, besides licensing and easy plugin development, the fact that it uses plain, unstyled contentEditables, so the stuff you're editing looks exactly like it will look on the real page.

I integrated Redactor as another editor option in Create.js a while back, but it looks a bit strange because it changes the styling of the currently active content area. Other than that it is very simple and clean!

Another valid editor option is Aloha, http://aloha-editor.org

You can use any (or even all) of these with Create, or integrate your own. The next editor I'm looking to add is CKEditor 4, as it also has an inline editing mode: http://nightly-v4.ckeditor.com/3627/samples/inlineall.html