Welp, I have a 3DS now. It's pretty neat.
If you have any questions you'd like an actual, flesh-and-blood 3DS owner to answer, COME AT ME!
Honestly, you should probably wait until this holiday season to pick one up, especially if you want the upcoming red color. There will also be a lot more games for it then. Still, if you wanted a black or blue one with Devil Survivor Overclocked or something, no time like the present with the new $170 pricetag.
Visually, it's very impressive, both the 3D aspects and the graphical level of the system in general. It's difficult to "place" how good the graphics look... somewhere between a PS2 and PS3 level, maybe? I should say that, apart from first seeing HD games being played on an actual HDTV, this is the first time in a while I've actually been "impressed" by graphics.
The 3D effect is actually quite well-implemented. It takes a little getting used to in order to hold the system at the "sweet spot" for viewing 3D, but it's not a difficult adjustment to make. You can adjust the 3D slider to make it "more 3D" or "less 3D", or turn it off altogether. Some games play at a higher FPS or look smoother if the 3D is off, so it's sort of a tradeoff you can switch between depending on the game or your mood.
I'm less pleased with the "upscaling" (or lack thereof) of original DS games. Colors look a bit washed-out and there's some blurriness. For games that use a lot of bitmap fonts or lots of sprites in general, this could make them end up looking kinda bad. I'd say polygon-based games (Okamiden) would fare much better.
Note that you CAN hold Start+Select to play the game in its original resolution, which ends up looking tiny on the 3DS' screens. I'm sure individual opinions of which is a better option will vary. Still, I'd like to see some kind of update that makes the colors look less washed-out when stretched, if nothing else.
By far, the biggest advantage to playing original DS games on the 3DS is the circle pad. For games like Dragon Quest IX and others that let you run around in eight directions, it's much easier on the thumbs than a D-Pad. It's also surprisingly easy to use even in games that just feature four-way directional movement and for selecting things in menus and the like, so you may end up not using anything else. It's definitely reassuring to have the classic D-Pad available for use, though.
You can also download and play DSiWare, which, if you're one of the many people who saw no point in purchasing a DSi, lets you catch up on some rather amazing digital releases. I've yet to download any of the original Gameboy games for the 3DS' Virtual Console, but the fact that these games are getting re-released after all this time is an amazing thing, no doubt.
Overall, it's a very impressive system. It definitely has the potential to meet and perhaps surpass the success of the original DS, and feels like a worthy successor to the name. I also don't feel like the system seriously lacks anything that a "lite" or "enhanced" version would make up for, unlike the original DS.