I just implemented this plugin on my site and I am amazed how simple it was! I spent nearly 6 hours configuring a similar gallery yesterday... I was finished in less than 20 minutes with CSS Gallery! While I'm no joomla noob, I'm not a power user! This was incredibly easy to install, implement and configure!
The only feature I would like to see is the ability to put the thumbnails to the left or right of the main image. Not a big deal but it would work better with my design.