[quote name='maigoyume']for some games you can't, i don't know why, F-Zero GX is one of those games and animal crossing[/QUOTE]
It's probably got to do with gaining an unfair advantage in the games in question. In Animal Crossing, having two separate versions of the same town could cause issues with things like random events and items (not to mention the prospect of traveling between the two identical towns and the character transfer involved with it); with F-Zero GX, it's probably due to the link to the arcade game that was never really pushed here in America, the one that allowed you to take your custom cars from the Cube version and race them on the masterpiece that was F-Zero AX.
Off the top of my head, the only other games that come to mind that
might have a reason for not allowing that would be the Pokémon titles, so you couldn't pull off any cloning tricks. Beyond that, I can't think of any other titles that would have that limitation.
With the vast majority of games, you're probably fine.
Back to the original topic...I've got a cheap third party 1019 card I got from Wal-Mart last summer that's been working flawlessly. That said, the only reason why I bought it was so that my sister could have an Animal Crossing town and so I could backup save files. My first party card is and most likely always will be my "real" memory card.
I'd absolutely get a first party one as your only or primary memory card, just because they're the most trustworthy.