The 3DS is the other Nintendo failed product of the last generation, although they save it by slashing the price low just before it's release and capitalizing on the quasi-monopoly they had with the DS.
While it was a good idea, it was horribly executed: the screen is horrible, and the design of the device pretty ugly. If they managed to do a clean, rip-less, HD screen with the parallax effect, then yes this would have been good.