I can't tell you how many chargers I have purchased that were not Apple certified so that when Apple does an update on my phone, the charger says it's no longer supported. Unless I find one for pennies, therefore, I no longer get charges that are not Apple certified.
Fortunately this one is. The great thing is that the USB cord stores itself on the charger for easy location and for convenience.
I do not find any difference in charging time for this device as compared to charges I buy directly at the Apple store.
I use my phone for GPS, lots of talking, very long trips, texting, googling, and everything else. My chargers get a real workout and this has not let me down.
Better yet, the light lets you know how to find it easily for grasping but, more importantly, to know it's working. If a charger is not plugged in just right, you can keep waiting for your device to charge with no result.
I have used this for my my phone and my ipod with never a negative result.