I now own for some time the 3DS and enjoy playing games like Resident Evil, Dillon or Kid Icarus. The circle-pad is great (seems to be stolen from the PSP, but better good copied than badly made yourself), streetpass is great, online is working good and backwards compatibility is so important if you see the big library for the DS.
But I'm not so sure about 3D. Yes, the games look gorgeous in 3D. But is it really a big difference for the gameplay? The only intelligent use of 3D besides making things look good, is in Kid Icarus. It is used to make the impression the bosses are bigger and for the gag with the flat walls with textures simulating a tunnel in the flight-part of chapter 5. But even Kid Icarus would work without 3D (or better: it works if you disable 3D).
But the inclusion of 3D has disadvantages. I'm not sure how much impact it has on the price. It may be unimportant on that front or add quite some amount. But it drains the battery (you need more backlight to support two images) and it does not work well in all situations, if you move the device too much.
So, sometimes I think the inclusion of 3D was a bad decision from Nintendo. On the other hand they advertise with this feature, and while streetpass and circle-pad are great, I have no idea if they would get the same public attention as the 3D feature. Maybe without 3D the 3DS would be only seen as a slightly better DSi and unsuccessful.
What do you think? Discuss!
P.S. Tagged it with RE:Revelations, as I get the feeling the game is worth a little more attention.