In the "yet another anecdote that may not work for you" department, here is my journey from svn to git on a Mac. My objectives were simple:
My experience with package installs is that if things start to go a little squirrely, give up and build from source. Git was no exception. Build from source didn't quite work either:
MSGFMT po/de.msg make: *** [po/de.msg] Error 127
This blog post got me past the first hurdle. Git was working, but the svn integration was not, so I followed this advice to reinstall subversion with Perl bindings. (This actually worked without resorting to source.)
Next, I followed these instructions to completely convert a substantial svn repository to git. That almost worked, but since my repositories are authenticated (duh!), I ran into this problem:
Can't locate SVN/Core.pm in @INC
This is caused by a missing Perl module, as documented here. After a couple of minutes fiddling with the multiple Perl installs on my machine to install to the Perl that git-svn expected, I was ready to go.
And with that I seem to be up and running. Total time: about 2.5 hours.