I'm using a Samsung quick charger on my G4. Phone charges really quickly, especially handy when you notice your phone is near flattened and you need to go out in a shortish while. 15mins charge gets you a very useable amount of battery life.
I assume it's a Qualcomm charger - from what I understand, these chargers don't give more than 2A, but put out a higher voltage (more than USB 5V), so can convey more power in the same time, but the phone has to have a Qualcomm processor, that can control all this magic, which the G4 has

