Here it is: the price point. $250 for a 3DS.
Is it too much? Well, considering that a DSi in Canada costs about $200, I'd say no, with the caveat that $250 just is a lot of money. Compared to the PSP, though… well, that's a different argument altogether.
There's no way I'll be able to pick this up at launch, if only because I can barely afford groceries and rent right now, so 3DS reviews will not be on this site for awhile. I'm bummed out about that, but I've also never gotten a console at launch… ever.
Anyways, to whet your appetite/whistle, here's a short trailer of the announced 3DS games so far. Everything is looking preeeeetty spiffy.