Among other, less important changes, version 3.3.6 fixes a serious problem regarding UTF-encoded text files. Please update if you are using 3.3.5.
Officially, SmartGit 6 requires OS X 10.7 or higher, but, depending on your system, it may be possible to get it starting on OS X 10.6.8, too: right-click SmartGit.app, click “Show Package Content”, navigate into “Contents/MacOS” and open “SmartGit” in a text editor of your choice. There you’ll find the line
if [ `sw_vers -productVersion | cut -d'.' -f2` -lt "7" ] ;
Change the 7 to a 6
if [ `sw_vers -productVersion | cut -d'.' -f2` -lt "6" ] ;
and save the file.