I have found this plugin to be enormously useful! The only issues I've had have been with the paragraph-editing mode.
First, the edit box always seems to be too small for the paragraph being edited. (Firefox 3.5.7 on Mac OS X 10.6)
Second, the text is enlarged after saving; does not happen with full-post editing. (Also Firefox 3.5.7, Mac OS X 10.6)
I am using the LightWord theme, if that will help debugging.