First: Github is a site (that does have a client) for using a version control system called git.
Here's a good comparison of the 2:
https://git.wiki.kernel.org/index.php/GitSvnComparison
In general, git can support a very branch-heavy development process more easily, and can be easier to use if you have irregular internet access (hint hint, good for at competition). Netbeans has integration for both systems too, I believe.