Having been unsatisfied with the suckerfish menu modules available at the time, I used Jason Jaeger's MenuMatic (http://greengeckodesign.com/menumatic) on another Joomla-based site I built. Since I found it so helpful and easy to use with Joomla 1.6, I posted the info on the community board. A few weeks later this module appeared.
Basically everything is ripped from the above website (including the code, all the default settings, the credits given in the description and some images on the demo site).
That said, the author of the module did a great job turning it into a module. Though most basic settings (such as colour and roundness of corners) still have to be done with css, the module is also highly configurable from the backend (configuring effects etc.).
I'm mostly commenting to give credit to Jason, but I have to say the author did add a fair bit in terms of usability and integration with Joomla.
All in all, great module.