Hopefully one answer to satisfy all PMs . Yes, the Gamecube memory card works perfectly and has no issue loading data (nor did it ever). It comports a lot more save spots than the original Nintendo ones, and it can be either a backup for everything, or take over as the main card for most/all games (unless you're one of those with dozens of games, then no one card can handle it alone ).
The firmware is the latest, I don't keep track of the number. It's the 2001B model, and yeah, that price is staying. There was once a guy trying to haggle to get it for $125 shipped, hahahaha.