If you are needing to display a HUGE block of images, and don't want to go through the process of uploading THOUSANDS of images into your Wp Db, then this is the plugin for you.
The way the images are displayed is simple and effective - no frills, but I'm sure that if you need slick displays you can find someone to CSS your posts into whatever you like.
I manage three photography sites, all of which have 1,000 to 20,000 images. I have not found a Wp uploader that is up to the task of importing all that - not to mention working on tagging and categorizing each image.
UnGallery allows you to work directly with existing folder structures and get the show on the road Post Haste!
NOTE - this plug in is all about FUNCTIONALITY - not about being slick and polished. For those who need the function it provides, this plugin is a "hole in one". If you need all this PLUS a super swanky flashy fizz-bang display, I suspect you need to look for a custom built bit of code (why not ask this plug-in's author about whether or not he'd take the job?).