Super Mario USA is my least favourite of any Mario platforming game, 2D or 3D, so I picked the original Super Mario Bros 2. I have never loved Mario USA/Super Mario Bros 2/Doki Doki Panic, and I never will, although I admit that its first level theme is really catchy. The caveat to my Japanese SMB2 pick is that I played the Mario All Stars version of the game, which makes the worlds substantially easier by allowing the player to save after each level, instead of upon completing an entire world. If I were forced to play the NES versions, I'd probably have a better time with Super Mario USA, although I wouldn't enjoy either game, really.