Has anyone been using this client, is it worth using as far as GUI's go?
For power users, look elsewhere.
I think it's a very simplified view of source control and badly needs to be iterated to appeal to power users.
That said, I'd recommend it for novices to source control.
I don't know why people are trashing this app. It's not exactly hard to use the command line if you don't like this app.
Using a GUI on git is just a convenience, and probably most useful for new git users.