When it comes to USB ports, all wall adapters are supposed to be the same since USB is an international standard. The worst that could happen is that you get a cheap or defective one that is not strong enough for your application and your battery will not fully charge or charge at all. I have one that came with a Blackberry and will not work with anything else than the Blackberry (one more reason I really hate them, but at least that was my boss' 600$). If the LED on your charger is not lighting up, then there are chances that your battery will slowly drain itself past the point where it will just die on you.
ALL OTHER AC WALL ADAPTERS ARE NOT THE SAME!!! There are not all different either but, if you don't know anything about electronics, it is wiser to stay on the safe side. If the charger or battery are getting hot beyond comfort to the touch, then something is wrong.