Playing games which are rich in graphics ?

it comes with 12 MP cam which capture sharp picture and also have 1.5 Ghz D.Core processor and 1 GB ram for lag free  multitasking and gaming.

the xperia u has better game perfomance but it does not has SD slot, it just can install few games on it with 4gb of internal. the sony xperia go has mali-400 that is suficient for gaming. i prefer xperia go

Xperia S being the playstation certified device provides the best in class graphics and 1.5 ghz dual core cpu and 1 GB ram are quite sufficient to hold the game.

Source(s)

I own one myself :)

Speed : Both of them are snappy especially because both have the same CPU, GPU and  RAM.

Screen: Xperia U has better resolution even though both have equal screen size.

Means Xperia U is better for gaming.

Battery : Xperia Go has much better Stand-by-time.

Camera :Similar while the Xperia Go has the advantage of taking photos under water,the Xperia U has the advantage of  having a dedicated hardware shutter key otherwise similar photos (no Big difference).

Data : Both have the same speed.

I prefer Xperia U since it is more unique and the better screen will make games look better and also the camera shutter button will help you to take pictures easily.

The note 2 has a greater screen easier to control

With Quad core