The next-best thing about 3DS? Turning the 3D off.

[Wiped]

It's just a case of getting used to it. When I first got a DS, I felt nauseous playing it because my eyes weren't used to moving '3D' (ie SMB64DS) so close to my face. I pushed through it and it went away after a few weeks. I'm sure the same will be the case for the 3DS.