This plugin gives you the flexibility to add Ajax handling for your comments to keep the page from having to refresh every post. The administration panel will allow you to customize your processing, success and error messages.
Additionally, this plugin gives you the option of setting up the WYSIWYG editor for comment submission as well. The admin panel will give you the option to show/hide various button groups for the editor and only allows basic editing capabilities. If logged in as administrator, you will still receive the full WYSIWYG editor for your commenting.