We've been playing around with the Jahia CMS Suite lately and have found it to be pretty darned good.  Other Java Open Source CMS's we've compared it to are:

- Alfresco
- Open CMS
- Magnolia

We liked Jahia for the following reasons:

1.  Of all of the above vendors, it seems the most "put together".  Alfresco is a close second in this category, but Jahia still beats it out.
2.  It contains a real portal/delivery mechanism which the others lack to support personalized content delivery
3.  United Content Hub and JSR 170 support make sourcing from other repositories much easier
4.  Full J2EE architecture, all the latest standards are followed stringently
5.  Deploying templates on teh file system make it easier to version control templates and deploy to multiple environments (dev, integration, QA, Staging, Production)
6.  Inline/In-Context editing isn't an afterthought like it is in other Java Open Source CMS's
7.  Supports Dublin - Core meta data natively
8.  Adding features to the end-user interface can be as easy as downloading a 3rd part JSR168/286 portlet and installing
9.  Documentation is plentiful and accurate.  In addition, if you purchase support, you really do get someone on the phone to help you
10. Multi-language capabilities are excellent for an Open Source package.  This is likely because it's a European based product and generally products out of Europe are better for multi-locale/language than US based products.
11.  Asset Management is robust with WebDAV support, versioning and metadata tagging on assets
12.  Importing/Exporting into Jahia is easy with the supported XML spec for content movement.  This also helps in multiple environments.
13.  You can use a real IDE (read Eclipse) to develop and debug templates.   No funky/proprietary template editors.
14.  Uses Lucene for search, Hibernate for Persistence and Spring for Dependency Injection
15.  Very scalable, clusterable.  This product is truly Enterprise Grade

In terms of Java based Open Source CMS's, Jahia is tops on our list.

Pricing depends on the support you require and your desire to publish enhancements back to the community.

I'll keep posting more things we like and things we don't like as they come up, but right now, this looks like a very decent for the price.