I do believe eGo is the brand name for this style PV manufactured by the Joye people. Riva is manufactured by a different company and does not call itself an eGo. It's similar to calling a tissue a Kleenex. Not all tissues are actually Kleenex brand, but we've come to use it as a generic term for one of those things we grab when we sneeze.
I'm not trying to be argumentative, just reporting what I am seeing here in my hands.
This was sold to me as a RiVa product and is indeed marked eGo on the box and has the soft rubber button that people remark on. The unit itself, of course, has no marking, just like any other eGo I have seen. The documentation references the 750ma battery, but carries no manufacturers data. *shrugs* Could be a knock off, could be real, no proof either way. However, it does the job and that's all that matters.
I'm mentioning all this in light of the normal slipshod way in which Chinese industry works. They are so consistent in their inconsistency. And so respectful of branding, copyright, patent, and IP rights. The way they work, I wonder if one Chinese manufacturer even has the right to sue another for branding, patent, etc. infringement. I would guess not, in the Chinese legal system.
Curious, no?