I imported this with my launch copy of MHX. It's a very comfortable N3DS grip, makes it feel like an actual controller. There is some play though, it's not as solid as like a CPP or Slide Pad on the old XL, probably because it doesn't lock in to anything.
You can slightly rock the 3DS at the...
Think of those cheap controllers that have composite out but multiply the cost by 200. It'll be running off emulators on an lcd.
The extra buttons are for people who use the joystick with their right hand. Basically makes the cabinet ambidextrous.
You'd honestly be better off buying a cheap...