There's quite a few easy-installable and lightweight CMS frameworks, and I've put my hands on quite some of them, but I always got stuck somewhere, trying to figure out how to do the impossible inside it. Yeah, I know, not many people have a hosted machine with more than MySQL and PHP pre-installed, but not everyone wants a 5-minute install and week-long module edits to make them work the way you want. Not for large projects.
Sometimes you just need a tank to break through things. Well, this is one. With a glossy polished chassis on top of it.
What's the gears then? Plain simple - Apache, FastCGI, Perl, XUL. If you work with web development, there's nothing to explain. Standards, speed, future. The framework is totally extendable, even the data structures can be tweaked to your will, if you need to edit more than the modules themself. As it's written in Perl, basically the whole CPAN is at your service. Through the months I've been using it, I've written my own modules, tweaking the existing ones, but also my own with a local db table, if you are into Perl - this is a piece of cake. Not mentioning, that I was a PHP fan once - I still am, having been transformed programatically to Perl in no time, but for large projects? No go. Cyclone3 beats any PHP engine.
I've seen probably everything running on this framework - multi-web portals with common user management, on a farm with multi-server and multi-db backends, e-shop solutions, flash-based pages, business pages, image-based pages with multimedia, import and export services, newsletter services, globally usable modules, local modules - you name it!
And what about the looks? Cool. The administration system works on top of Mozilla's XUL engine, using pretty much everything it has to offer. And it gets better with every release, from tiny enhancements to great leaps in functionality. Everything based on the same principles as you use every day on your desktop. Yeah, there may be things that require some time to get used to, as with every system, but your daily work is just smooth in here. Everything divided by type - you don't have to search for an article in the whole page complex - it's in the articles content tree. Same with other types.
But what about the site tree? No, not what you think, it's not static ;) You can administer the site map from the CMS interface, too. Along with users, groups, and so on.
Overall? If you're looking for a dependable, expandable, and easy-to-implement framework with really usable interface - definitely check this one out!