Hi LOTR
the jum versions are not very different. Think of it as a pre-beta beta.

--a different installer (drag and drop from the dmg rather than a double-click installer). This helps troubleshoot/check installer issues

--it's built from the CVS, so includes all the changes (many not fully tested) at that time (handy for checking out new inclusions between official releases).

--other changes (Jens-Uwe listed them here

Jens-Uwe has given us OS X users who don't know enough to compile our own versions an easy way to use the CVS versions, and he gives his changes and fixes back to the project. Much appreciated.