Ok, so I got a chance to go hands-on with the 3DS yesterday and have to say that I'm impressed.
Here's the list of games I got a chance to play:
Biohazard Revelations
Dead or Alive Dimensions
Ridge Racer 3D
Super Street Fighter IV 3D
Unfortunately, I didn't get a chance to get my hands on Ocarina of Time, but I feel the games I did play gave me a good grasp of the capabilities of the system.
All in all, the 3D effect works better than advertised. What I have to say is that the effect doesn't seem to come out of the screen, but rather deeper into it. Having the slider to adjust the 3D effect was really nice as well if only because I could compare 3D and 2D. Graphically, the games could easily compare with the PS2 in terms of detail. Getting used to the analog nub was a little tricky at first, but definitely performed better than the nub found on the PSP. In particular, having a concave shape worked well in maintaining a thumb grip. My one real gripe is the glossy finish (inside and out) which will be a major fingerprint magnet.
The games did play well and were technically proficient. Ridge Racer 3D needed some work on the 3D implementation, but the others looked at or near ready for release.
After playing the 3DS, I am now a believer that this is 3D done right. Considering where I am right now, I honestly don't know if I'll get one, but I'd be lying if I said I wasn't considering it. ¥25000 ($299) is a lot to pay for a handheld, so I'll most likely wait for the first price break, but if the US release has a lower price (say, closer to $199), this little machine will sell out fast.