I've played a handful of 3DS games here at Nintendo's press event in New York and learned a good bit about the hardware in the process. As the images indicate, it bears a strong resemblance to the standard Nintendo DS in basic look and feel.
Opened up, the glossy black bezel around the top screen initially looks a little incongruous with the rest of the device. But, as with Apple's recent MacBooks which have a similar treatment, it pays off in providing the display a good viewing background.
This particularly comes into play with the 3D effect, for which the black finish provides a good backdrop. Any other treatment could potentially have been distracting and disrupted the 3D.
Nintendo did a great job with the analog control stick. It fit naturally right under my thumb and the concave top and soft coating gave a good sense of grip and control. The range of motion for the stick likewise feels comfortable. Unlike the stiff nub on Sony's PSP, the stick on the 3DS moves with the resistance balanced to keep it from being loose while allowing it move smoothly.
The other controls--the D-pad and buttons--appear to be borrowed directly from the DSi. Though they may appear to be part of the touch screen, the new "home" row at the bottom center of the 3DS are in fact physical buttons. They have the common membrane switch mechanism underneath them and I could feel a subtle click when I used them.
How well and to what degree the 3D effect works varies a good bit depending on the game. The slider for controlling the strength of the 3D proved to be much more important than simply a way to turn it on and off. With each game, I needed to take a moment at the start to dial-in the 3D. None of the games actually felt good at full intensity and over the ones I played I never seemed to use the same setting twice. Viewing distance and angle also seem to factor into getting the setting right.
As far as "seeing" the 3D, the screen exhibits differing sensitivity to being viewed off-angle, but in all directions the sweet spot is fairly narrow. The 3D fell apart fairly quick if I moved to looking at the screen from above. I'd guess that it was only a few degrees of 'over the top' before it started to blur. On the other hand, looking at the screen from low angles, the effect held together all the way down to looking at the angled screen from level with the lower deck. Side-to-side tolerances are about on par with that of 3D TVs using glasses--get a few degrees to either side and the screen becomes an eye-crossing blur.
For less-intensive games, the viewing window shouldn't pose much problem. Action games, though, could be more challenging. All 3DSs here are tethered, making it hard to hold them exactly as I would without the block on the back, but in Madden for instance, getting excited about a play and jamming the stick to make a move sometimes jostled the 3DS around enough to momentarily break the 3D.
There's also the sleeper features of the 3DS that may or may not become more than a novelty (remember the GameBoy sticker printer anyone?). Take 3D photography. It looks cool but given that it requires the viewer to have a 3DS as well to see how valuable will that be in world where we love to share pictures online? At $250 the 3DS is probably in range for those excited about the technology and the "wow factor" of it.
Beyond that, I think the first year or so will be telling as to whether playing games with the device in your hand can be done steadily enough to make it consistently good experience. We'll know soon enough as the first gamers get their hands on the 3DS next month in Japan.
Cool write up. Did you have much of a chance to play original DS games on it?