I haven't tried that one but I have two Ankers and a QCell, all from Amazon, and they all work great. I don't even plug my phone in anymore, I just carry a fully charged spare and throw the empty one onto the external charger when it runs out.
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?