The only think missing is the LB and RB.

Doesn't have any LB or RB buttons on it therefore it's not compatible with a lot of games such as Need for Speed

The only drawback is the removal of the right bumper (RB) and the left bumper (LB)

It does lack the two trigger buttons of normal controller (LB and RB), so is only useful for racing and flying games that wont require those buttons