Decided I am gonna upgrade from my pen styles to an eGo. Been shopping around and I have noticed many vendors selling different versions of an eGo battery. Are there many different makers or just one and they get rebranded??? Or am I missing something all together??? Are all of them created equal??? I have also seen one called a vGo. Any info or links to the differences would help. Don't wanna buy junk. Just looking for the best basic 900mAh eGo. Doesn't have to be a passthrough and don't really want a vv.