I think the title sums it up. I just want to know why one or the other is better for continous integration builds of Java projects from Svn.
As a long time CruiseControl committer and someone who has never used Hudson I'm pretty biased, but my take on it is:
Hudson is much easier to get up and running (in large part from a nice web interface) and has a very active plugin development community.
CruiseControl has support from lots of 3rd party stuff and has the benefit of doing some neat tricks with the xml configuration like plugin preconfiguration and include.projects which lets you version the configuration information with the project.
If you're only going to have a few builds I think Hudson is the clear winner. If you're going to have lots -- and don't mind the xml -- then I think CruiseControl's xml configuration tricks become a real strength.