For example, I wanted to add the 'Add This' icons to my articles, I could enter it using the codemirror editor, but the minute I would switch to TinyMCE and open my article, it would be removed.
With Jumi, I entered the code through the component and call it at the bottom of my articles. Done!! No more problems with 'Add This'.
I had the same problem embedding YouTube videos, I made a little code snippet and since Jumi allows you to add a parameter when you call it, I made the parameter the YouTube #ID. Done!!
So instead of waiting for Joomla! 1.6 extensions and plugins to be coded by other people, I can just use jumi to cover the gap until developers have caught up with 1.6 compliant extensions.
I highly recommend it, and it's 100% free!!