Do you need a tool to compare some CMS softwares without visiting the website of each software and reading all related information that might cause you headache?
CMS Matrix allows you to compare up to 10 content management systems at once. Each software is described into some parts which refer to its system requirements, features, security, support and built-in applications. So, for people who keep their eyes into details, this feature will help them pretty much to find the suitable software for their website.
Moreover, you can also rank and rate the software for its usability, flexibility, capability, performance, interoperability, managability, security, scalability, install process and upgrade process. I think, any input of yours will count and help other users on their searching to the ‘right’ software.
Conclusion, this website becomes an ‘all-in-one’ place for all your CMS comparison.
Kemas Antonius 
I am not a fan of CMS, however walking along their listing and reading FAQ, I have a little prediction that they will be busy with free (mostly GPL?) CMS. They are best at their free and community, but perhaps some of us also want to know commercial features of CMS.
For example, I ever read from Diki Andeas that Astaga.com used Vignette — http://www.diki.or.id/blog/index.php?id=131_0_1_10_C — a product which really I never heard before. If most of free CMS are really powerfull even for busy websites, what is the real advantage of commercial ones? Robust and ability to handle very large database?
While they are more expensive…
According to my opinion, the big differences between the free and the commercial CMS products lie on the features and the support available to the user. If you purchase one commercial product, at least you will get a certain period of guarantee that all problems you encounter during the use of the product will be supported. After all, any updates would be free available for such product during its lifetime.
Free or open-source CMS products as it referred by its name, all work are done by the community. If you have questions regarding the use of the product, there is a possibility that your questions would be not answered properly. As result of it, you have to spend more time to find out the solution.
Features also play a big role in differentiating whether you use the payed or free one. Most of the commercial products will support the recent and the latest technology which is important for corporate use. Meanwhile the free one mostly supports the basic one. But, fortunately nowadays there are some brilliant people who already know how to implement and build the techonology into the free products, so everyone can get many benefits of their work.
I, myself, as someone who intensively use the free open-source products in any projects I have, will always promote this type of product to everyone and I’m sure the future of this will be bright.