I have a 2DS Panda Unit (aka, Test Unit).
I actually didn't want to get it in the first place, but it was a month before release, and NOA already started selling them on WarioWorld, so I thought, why not.
As soon as I got it, I started to love it.
Although I can't play any Retail 3DS nor DSi-Enhanced game on it, I can still play all DS games on it.
From what I've experienced, it plays pretty well, I finally use the Circle Pad in Mario Kart DS decently, the L and R Buttons are accessible and have a better grip, and it looks cute in real life.
In fact, I love it even more than my 3DS systems, I honestly think the 2DS is what Nintendo should have made at the very beginning of the entire 3DS genno, but then it'd lack their main USP: 3D without glasses.