Got my 3DS today and am loving it so far... got "LEGO Star Wars III: The Clone Wars" and "Super Street Fighter IV" along with it. Both games look fantastic, although I've noticed some frame-rate drops in LSW once it gets crowded (or full of visual effects)... turning off the 3D helps a lot, but that's hardly an option for me
It's been years ago since I experienced an auto-stereoscopic display, and I must say the 3DS' screen does it really well. The intergrated 3D camera(s) though is crap... the 3D works fine, but the image quality is horrible (especially since it doesn't use the full 640x480 pixels of the camera, so that you can "re-focus" the image while in the photo viewer). Still, putting stereoscopic photos of other cameras (like the Fuji Finepix Real 3D) works fine, showing a much better image quality (though no option for re-focusing the photos while viewing). I can't wait for 3D movie trailers to become available for the device.
I agree that the concept of the AR games is clashing with the "don't move your head"-concept of the screen, but it's still a nice feature which is very well implemented.