Shameless plug: I recently built a new linux GUI git client. The people who use it really like it. Still working on docs to better explain what makes it different. Like GitHub's client, it's more than just a wrapper around the CLI, but unlike GitHub's client it exposes git's full power (tags, cherry-pick, rebase, etc.)
If you'd like to try a new linux gui client, give it a spin!
Video in action: https://www.youtube.com/watch?v=X4UQpGk1Ry8
Free download Win/Mac/Linux: https://secure.diffplug.com/versions/1.6.1