I have brought German version of OmegaT to the current state of things. A lot has happened since the last update of the German GUI and so there were 200+ new segments (out of ca. 750 in total) – this by itself speaks for the development of the tool.
In case you haven’t heard of it, OmegaT is probably the most popular open-source CAT tool (or TEnT for translation environment tools as Jost Zetzsche calls them). It is a Java application and therefore runs on all platforms – Windows, Mac, Linux, etc. OmegaT has been designed with openness in mind and therefore supports many formats that other tools have been ignoring, such as PO or OpenOffice. Also, open standards play a big role in the architecture (TMX, XLIFF, SRX…) and the TM created by the tool is directly accessible in TMX form in the projects folder.
Part of the openness means that everyone can contribute their localised version of the GUI and the documentation. If you also would like to join the OmegaT translation team, have a look at the website and/or join the mailing list.