The PJ-00X cartridges are probably one of the best features of the Power Joy line, as they offered the choice of many great Famicom/NES titles. Mine came with the PJ-008 and I've seen different lists of games given to the same # cartridge, Chinese quality control there, huh? But the great thing about the cartridges is the simple fact that they work in an NES (w/ converter) or a Famicom, obviously as the Power Joy is a NOAC.
One of the main reasons I enjoy the Power Joy is due to its all-in-one design, so I don't need to hunt down accessories and parts if I want to play the thing. The Power Joy is strictly utilitarian but quite comfortable, as well as painfully obvious that this was spawned from the breeding of a Nintendo 64 controller with a fighter jet model kit. One of the major features, at least to me, is that unlike the Super Joy units the joystick on the Power Joy is fully functional, yet only a digital pad and not analog.
And finally we reach something that Super Mario Bros. taught us all those years ago, other people want to play too, and they have as much right as we do, us controller hogs! It took me a while to actually track down a Power Joy second player controller, but I did and its fairly standard, yet pretty good. My only complaint would be that the spacing on the grips is a bit strange, which I personally can't use it for too long, but then again that could be a ploy to keep people from wanting to become player 2.
I currently own the Power Joy and Power Joy Voyager, but I hope in the future I will find more Power Joy systems and even more of the cartridges. I'll never forget the first time I passed up an absolutely complete Power Joy for $10 at a thrift store, but through time and patience I've pieced one together, with a spare one for parts if needed. The Power Joy is nothing more than pure Chinese piracy and I don't really favor it over any of my other consoles, or even Famiclones, but it was my first and thus I will forever remember the joy and excitement of exploring a world that was completely new to me.