Personally, I'm not buying a 3DS until I can try one out for a while. Everyone that has had there hands on one to review says different things about how long they can play in 3D before it hurts their eyes. Some as short as a few minutes while others never have trouble. My hang up is I don't want to pay $250.00 for something if I can't use its primary selling point to full advantage.
I hope I can play it though, cause I would love Mario in 3D, not to mention all the other neat things they are cramming into it.