content: I'll add my 2 paisa to this. Capacitive touch screens are extremely sensitive to noise from a bad charging wire. Your average bridge rectifier and a low pass filter in cheap rip off D.C. chargers won't cut it. Apple's chargers literally have a tiny ARM cpu in them - it's sole purpose is to perform sophisticated control over the DC signal over the charging cable.  Will your cheap adapters not work at all? Well, most of the time you don't have water droplets or any charged surface or varying magnetic fields near your touchscreen while you use it - so a cheap adapter can work for you.  On the other hand, apple can not make a product that can damage your touch screen or endorse other chargers that can damage your touch screen.  I'm just talking about the implications of an inferior charger on a touch screen here. There are also the various antennas, pmic chips, magnetometer sensors etc to worry about. Buy the original- there's a ton of technology behind the scene that's pretty incredible if once you are aware of all that's going on with that little charger.