The motion control of the MotionFX
is actually pretty good. The adjustability of the tilt mechanism allows you to set it to work with the angle you normally hold the controller at, while the fact that it is designed to attach to your existing Sony Dual Shock controller means you don't have to get familiar with a new controller with a different feel.
While the MotionFX can be used with any game that uses the Dual-Shock controller, certain games lend themselves to tilt control more than others. Driving games and flight games spring to mind, for example. Other games may be a good fit as well, but there is a bit of a learning curve, as the tilt control is a new control dynamic.
One interesting thing about the MotionFX is that the settings are adjusted using the Sony Dual Shock controller. The controls make sense, pressing SELECT and down on the RIGHT STICK (R3) will set the MotionFX to control the right stick. Pressing SELECT and down on the LEFT STICK (L3) will set the MotionFX to control the left stick. You can also adjust the sensitivity of the control in a similar manner, holding select and using TRIANGLE to increase the sensitivity or X to decrease the sensitivity. Another nice feature of the MotionFX is the ability to set the "untilted" or "centered" position to what is comfortable for you. This is done, when the MotionFX is on. by simply pressing the Engage button (on the MotionFX, itself) once. The settings are useful and somewhat intuitive, and the tilt controls are dead-on.