This is a series of post starting here, in which I look at different CMS installations and despair.
At the end there’s only two left to consider, Magnolia and Joomla! And I’ll go for Magnolia first. Simply because I will need to tinker a fair bit with the system, and Magnolia seems a lot more friendly to a Java developer than Joomla! Don’t get me wrong, I can program in PHP as well, but I’d rather not, and the Joomla! template PHP is rather cluttered.
As for extensions? This may be a problem for other sites, but I don’t think it will be for this particular setup. Even if so, I can install some WebService stacks parallel to the Magnolia apps and use JSTL and ordinary JSP to serve the content in the templates.
Multilingual content? Joomla! has it, but all too contrived. Doing separate directory structures for separate languages may not be optimal for everyone, but it’ll work for this installation. And I can already see myself doing some templating tricks for the rest.
Joomla! is a runner up, and if the client is not happy with the Magnolia editing functions I’ll have them try Joomla! instead. In either case I think I’ll be happy to work with any of the two systems.