How do I checkout an SVN repository with Git?

Committing changes is local, as with normal Git. You can do that as often as you like. It does not touch the SVN repository.

git svn rebase

updates and merges changes from the SVN server (like "git pull") and

git svn dcommit

pushes back your changes (like "git push") to the SVN server as individual SVN commits. They claim in the documentation that it is totally transparent, SVN users do not see that you are using Git.