Choosing a Version
You should always use the current stable version, which is 2.2.12, if you want to work with Bluefish. There are packages for various Operating systems (Linux, Windows, Mac) and Linux distributions available from the project webpage or from sourceforge.
If you are interested in latest features, you can download and compile the source code which is available via SVN (you find instructions here). But be aware that this version can contain bugs. If you are interested in helping, it is of course a good way to use the SVN version. If you encounter a bug, you can report it to the developers so they can fix it.