If I could hook more than one GC controller into that at a time, I'd probably go for it.Though, if you do scrape up a few extra bucks, there is this option.
http://www.amazon.com/Mayflash-Nintendo-GameCube-Controller-Adapter-Wii/dp/B00BS520SG
Thinking about getting one myself.
I'm really hoping that when Super Smash Bros 4 comes out, Nintendo will let us use 3DS's with the game as extra controllers the way Sony let people use PSPs/Vitas. That way no one gets saddled with a Wiimote.