Hello, we do not have a PS VITA, but my son who uses the Anker says its compatible with most devices. It comes with several USB cables. The description of the device on the Amazon website does say that its suitable for a PS VITA.
This Anker charger is a bit of a beast. I don't see any reason why it wouldn't work on a Vita. Looking at Playstation's manual for the Vita PCH-1000 and PCH-2000 models both suggest that a USB cable attached to a PC won't supply enough power unless the device is turned off completely. However I think the Anker may be able to charge while you play. As I said, it's a beast.
http://manuals.playstation.net/document/gb/psvita/basic/charge2.html [Vita manual on charging]