You mean this one?...
http://i.ebayimg.com/t/EA-Sports-MEMORY ... ~60_57.JPGhttp://i.ebayimg.com/t/EA-Sports-MEMORY ... ~60_57.JPGDefinitely is not licensed by Nintendo, there's no Nintendo marking any where on it. They call it a "memory card," while Nintendo's official product is the Controller Pak. Also, it's the same design as the Performance third party card. If you look on the label on the EA card, you can see it says made by InterAct for EA or whatever. I think InterAct and Performance are the same deal.
http://i.ebayimg.com/t/Performance-MEMO ... ~60_57.JPGhttp://i.ebayimg.com/t/Performance-MEMO ... ~60_57.JPGIs it reliable? That's hard to say. I've owned a Performance memory card, like the one pictured above, since back when. I'm pretty sure I had to reformat the card a few times. I don't usually use it, it's kinda just a back up or a temporary place holder.
edit: By the way, in case you're curious, I'm pretty sure those cards were designed like that so that they can easily be removed from Performance's Tremor Pak Plus. See here...
http://ecx.images-amazon.com/images/I/714N9C0AT3L.gifhttp://ecx.images-amazon.com/images/I/71Y5TS30YGL.gifThat's how I got my Performance memory card, came with the Tremor Pak Plus. I made the mistake of sticking a regularly shaped N64 card in there once, it's really hard to get them out.