I am currently using Sixaxis on Shadowgun. I would never have played more than a couple levels of the game using on screen controls, but with sixaxis I look forward to playing it everyday.
There is some weirdness with it though, and I am not sure if it is shadowgun, or the controller. It doesn't seem to like multiple button presses. Most noticeable when pressing reload, and trying to shoot right away. The shoot button is not registered, until you release and re-press it.
I need another controller and am tempted by the Phonejoy. Does anyone know if the Phonejoy has the same issues on Shadowgun?