I'm a bit cheap (g), so I hesitated to buy Wysiwyg Pro until I saw the refund guarantee. But it is worth the money. It seems more stable and reliable than many of the Joomla 1.5-compatible editors, and offers a number of advanced features I need.

What really impressed me, however, was the fast and helpful response from the developer when I requested advice on how to change some of the defaults. In one day I got back clear instructions that allow me to modify the editor's setup to precisely fit what I need to do.

For basic editing, Wysiwyg Pro seems just a little slower than TinyMCE and some others. So perhaps there's a tradeoff of feature depth for speed.