While not a necessary controller, it is a lot more comfortable and maneuverable than using a Sixaxis or Dualshock 3 controller with one hand. Also a lot better for left handed people I'm sure.
It's very sturdy, the d-pad is great and easy to reach. As are the other buttons on it. I haven't had any battery life issues. My only gripe is that mine didn't come with a strap.